Main Sources

Ricardo Cardoso and Isabel Breda-Váquez (2007) Social Justice as a Guide to Planning, Theory and Practice: Analyzing the Portuguese Planning System.

International Journal of Urban and Regional Research, Volume 31.2, June. pp. 384–400. Joint Editors and Blackwell Publishing Ltd.


Vítor Oliveira and Paulo Pinho (2008) Urban form and planning in Lisbon and Oporto. Planning

Perspectives, Volume 23. pp. 81 — 105. Routledge, London.



1) Manuel Texeira (1992) The

ilhas of Oporto and the Corticos

of Rio de Janeiro: the similarities

of form, the adaptation to local

conditions, the strategies for

conservation, Lisboa. pp.124

Main Source

Gaspar Martins Pereira (1994) Housing, Household and the Family: The ilhas of Porto at the end of the nineteenth century (Oporto). Journal of Family History, Volume 19, Number 3. pp. 213-236. Carleton University , Canada.



1) Manuel Texeira (1992) The ilhas of Oporto and the Corticos of Rio de Janeiro: the similarities of form, the adaptation to local conditions, the strategies for conservation, Lisboa.  pp. 124


2) Paulo Castro Seixas (2000) Ilhas and Condominios in Porto: anthropologicak urban structure and the social cohesion problem. Porto. pp. 2


3) Adapted from Gaspar Martins Pereira (1994) Housing, Household and the Family: The ilhas of Porto at the end of the nineteenth century (Oporto). Journal of Family History, Volume 19, Number 3. pp. 213-236. Carleton University , Canada. pp 221


4) Adapted from Gaspar Martins Pereira (1994) Housing, Household and the Family: The ilhas of Porto at the end of the nineteenth century (Oporto). Journal of Family History, Volume 19, Number 3. pp. 213-236. Carleton University , Canada. pp 225



The ilhas of Oporto form an interesting subject of study, revealing difficult relationships with Portugals socioeconomic climate at different stages in time.


In the past chapters has been described how the ilhas, inspired on a mediaeval building concept, formed the only possible solution to the housing problem Oporto had during the end of the nineteenth century. The same societal shift responsible for the exodus of the countryside (the civil war) made it possible for the ilhas to be built due to its new structure of ground ownership.


Oporto’s economy was only able to thrive on underpaid workers. Due to high food prices, housing rents were a critical factor in the success of the city. They had to be low enough to be suitable for the working class, but also in order to keep the (already very weak) economy of Oporto up and running. The same phenomenon can be found in other rising industrial societies of the 19th century, for example Rio de Janeiro and the larger British cities.


The weak economy also constituted in elaborated family-survival strategies, in which, like in rural life, the extended family worked together in order to make a living. The ilha formed an exceptionally stimulating site for these practices, allowing for great internal dynamics to fit with the needs of the family. As we already concluded social relations were often very strong, opposing strongly to the poor public image that was imposed on the inhabitants.


The people responsible for the building of the ilhas were often not very rich themselves. They too were reliant on the extra income that could be made from the cheap housing solution. For a long time this was an excellent strategy for the community, until disease and bad health became an important issue in society.


For more than a hundred years, many governments tried to ban the ilhas. But in the abscence of any alternatives people went on using the ilhas and even build new ones. Portugal fails even nowadays in finding answers on the housing problem and the existence of the ilhas. Although a member of the European Union since 1986 Portugal still suffers from the way of thinking of the planning system during the dictatorial regime. As time changed, so did urban planning, but very slowly.


Even now the ilhas remain in use, although for different reasons than in the past. Certain groups of residents tend to inhabit the dwellings, ranging from illegal immigrants to young starting families on the housing market. This shows that Portugal still has not succeeded to build affordable housing providing desirable circumstances. Ilhas remain a necessity in Oporto’s society, but can’t the ilhas be regarded as part of the Portuguese cultural heritage?

Main Source

Manuel Texeira (1992) The ilhas of Oporto and the Corticos of Rio de Janeiro: the similarities of form, the adaptation to local conditions, the strategies for conservation (Lisboa). Traditional Dwellings and settlements working paper series volume XLV, pp. 111-156. University of Californa, Berkely.



1) Manuel Texeira (1992) The ilhas of Oporto and the Corticos of Rio de Janeiro: the similarities of form, the adaptation to local conditions, the strategies for conservation, Lisboa.  pp.114


2) Gaspar Martins Pereira (1994) Housing, Household and the Family: The ilhas of Porto at the end of the nineteenth century (Oporto). Journal of Family History, Volume 19, Number 3. pp. 213-236. Carleton University , Canada. pp 215


3) Paulo Castro Seixas (2000) Ilhas and Condominios in Porto: anthropologicak urban structure and the social cohesion problem. Porto. pp. 2


4) Gaspar Martins Pereira (1994) Housing, Household and the Family: The ilhas of Porto at the end of the nineteenth century (Oporto). Journal of Family History, Volume 19, Number 3. pp. 213-236. Carleton University , Canada. pp 220


5) Same as previous. Entire population size from: Cristina Vieira. Porto Alegre é a capital do chimarrão ( Retrieved on may 1, 2010.


6) Portrait of John VI, King of Portugal; Wikimedia Commons.


7) Fátima Loureiro de Matos & Rosa Maria Veloso Vieira Rodrigues (2009). As ilhas do Porto: Lugares de Resistência (Oporto). Revista Eletrônica de Geografia, v.1, n.1, p.33-57. Rio Claro, Brazil. pp. 38


8) Gaspar Martins Pereira (1994) Housing, Household and the Family: The ilhas of Porto at the end of the nineteenth century (Oporto). Journal of Family History, Volume 19, Number 3. pp. 213-236. Carleton University , Canada. pp 215

Alke van den Berg

Main Source

Manuel Texeira (1992) The ilhas of Oporto and the Corticos of Rio de Janeiro: the similarities of form, the adaptation to local conditions, the strategies for conservation (Lisboa). Traditional Dwellings and settlements working paper series volume XLV, pp. 111-156. University of Californa, Berkely.

1. Typology

by Alke van den Berg


Research has resulted in the distinguishing of three types of ilhas; the basic ilha, the independent ilha and the two-storey ilha, also called “ilhas verticais, Portuguese for vertical ilhas. The latter two are actually variations on the basic type, which can be considered as an archetype. Of at least the basic and independent ilha there existed versions that occupied not only a single plot but two or more. Now will follow an explanation of the three different types in which our focus will lie on the basic ilha.


Basic ilha (fig. 1.2)

The ilhas of the basic type were built in the back of the plots of middle-class houses. These plots were narrow, often only  five and a half metres wide, but deep; up to one hundred metres or more. An ilha that was built on a single plot consisted of one row of dwellings that could be up to twenty houses long depending on the plot. Most of the time the ilha dwellings would measure four by four metres. Since they were only one storey high, that means that the total surface occupied per house was only a mere sixteen square metres. However cases existed where the area of the houses of an ilha only occupied nine square metres. A path would fill up the remaining width of the plot that wasn’t occupied by dwellings.  It would  provide access to the houses in the ilhas and would also allow the inhabitants access to the shared lavatory units within the complex.


The middle-class houses were built attached to each other, so that they formed a traditional closed building block. Therefore it was impossible for the dwellings of the ilhas to have a direct connection to the street. An indirect connection was made possible by a corridor through the middle-class house, that was one and a half to two metres wide, but on some occasions only a single metre. If the ilha and the main house were built at the same time, this corridor would be integrated in the plan of the main house and often get its own door that was integrated into the façade. If this wasn’t the case a corridor would be added later disrupting the original plan and façade. In certain cases it also happened that the middle-class dwelling did not take up all the width of the plot, and the ilha behind it would get its own alleyway to provide access to the street. In these cases the ilha and the main house were built at the same time.


The houses of the ilhas were built in such a way, that they only had one free frontage; the façade facing the path that led to the street. The other walls of the dwellings were either adjacent to another house or to the border of the plot. Because of this it was only possible for a house to have sunlight come in through one side. The small dimensions of the houses made sure that, in general, there was only place for one window and one door. This way of building was the most rational under the restrictions of intensive land use and reduction of building costs.


The construction of the ilhas was very poor. The external walls would be made out of single stone walls and on the inside space would be divided into three parts by simple wooden partitions. These partitions often would not even be complete; missing a door (that would be replaced by a curtain) or not reaching the ceiling. They divided the space into a living room that doubled as a sleeping-room, a kitchen and a second, smaller , sleeping-room. The roof was made of a wooden construction covered with roof tiles. Often a few years after their construction the houses would start to decay rapidly in the damp climate of Oporto.


Not only the construction, but also the facilities and services in the ilhas were poor. In most cases there would not be a sewage system or a water supply, so the inhabitants were to use cesspools for sewage. Even after the construction of a new sewer system in Oporto, only seven percent of the ilhas were connected to it. The lavatories were common to all inhabitants, and there was an average of only one lavatory for every five houses, which came down to twenty-five people. Domestic water supply, although established in Oporto in 1882, was non-existent in the ilhas. Sometimes an ilha had its own well, though the nearby cesspool made the water undrinkable.


As mentioned earlier, the basic ilha was not exclusively built on one plot, but sometimes would cover multiple adjacent plots. In the case of one ilha covering two plots, the houses would be placed in two lines on both sides of the location, opening onto a central path common to both rows of houses. Naturally these multi-plot ilhas would consist out of more than the average twenty houses; the biggest ilhas could have up to one hundred fifty houses. Other configurations for multiple plots can be found in figure 1.3.


Independent ilha

Independent ilhas were, as the type name implies, built independently from any middle-class house. An ilha built on one parcel would have two rows of houses on either side of a central path that would connect them directly to the street. The dwellings of these ilhas would come up to the street. The houses at the street side would have two facades where light would come in, instead of just one like the rest of the houses. The living conditions in the independent ilha did not differ from the basic ilha.


Two-storey ilha (or ilhas verticais)

It is unclear if the ilhas of the two-storey ilha had the same layout as the basic ilha, the independent ilha or maybe could have both. However, this type usually had better housing standards than ilhas of the other types. Internal streets were wider, the area per house could be as large as ninety square metres and, as the type name implies, they would have two storeys. Ilhas of this type were rare because they represented bigger ventures and larger investments. Generally the size of the two-storey ilha was larger than ilhas of the other types, probably covering multiple plots, although no evidence for this has been found to back this statement up.


2. Rua de São Vitor 49

by Alke van den Berg


For this course it was necessary to choose a social housing project to analyze. The ilhas however neither are what is called social housing in its modern sense, nor one project. It’s a typology. Therefore it was hard to find an ilha to present; there isn’t much information to be found on one specific ilha. Luckily we were able to find the original plans and elevations of an ilha, that we were able to locate, after some detective work. This chapter is not really meant to analyze the ilha at Rua de São Victor, but to show an example of how the ilhas are integrated into their surroundings. As just mentioned there’s very little specific  information to be found and a visit to the location was impossible, so unfortunately we had to rely on aerial photographs and general information for this chapter.


The ilha at Rua de São Victor 49 is a typical example of the independent ilha covering two plots, of which one plot is actually cut off in a diagonal manner.  It contains eleven dwellings that are laid out on both sides of a central path. The building block of which it is a part lies next to the steep banks of the river Douro and because of that the plot of the ilha contains height differences. The ilha has nicely been adapted to this landscape and was built with several levels connected by stairs. This can clearly be seen in the section in figure 2.1.


In the middle of the ilha, at the end of one of the rows of housing, the lavatories can be found. From the plans can be made up that there were two toilets and one washing room. If we take the average of four people living in each house that means that here were two toilets for sixty inhabitants. Now this number may be slightly too high since not all dwellings are of the normal ilha size, but it still a large number none the less.


It is unclear what the current state of the ilha is.

3. Emerging of the Ilhas

By Robin Verstappen


3.1 Historical context

The coming into existence of the ilha housing is heavily interwoven with Portugal’s history and socioeconomic development. One of it’s most important causes originates from second half of the 19th century, when Portugal’s agricultural economy started to deteriorate rapidly. According to the “First parliamentary survey on emigration” (1873), Portuguese farmers “can not obtain food in the places where they live”.1 As a result, most salaried rural workers were forced to move to the city. It didn’t take long till the farmers themselves also felt the need to relocate.


Meanwhile, in Portugal’s main two cities , Lisbon and Oporto, industry started to flourish. An initial demand for labor attracted the exiled farmers, and between 1864 and 1900 the population of Oporto nearly doubled, growing from 87.000 to 168.000 inhabitants. Three quarters of these were immigrants from outside of the city. In despite of their hopes for a better life, the newcomers oversaturated the labor market. Unemployment rose, and those who did find jobs were paid very low wages.


Here, it is important to note that Portugal never went through a massive industrial revolution as we know it. There was some mechanical production, but industrialization remained backwards and heavily reliant on low cost (often manual) labor.2 Later on, this will be discussed in more detail.


Around 1880 living conditions started to worsen rapidly. Wages were not corrected with inflation, while the price of food increased enormously. Eighty percent of the income had to be spent on food, leaving only very little money left for rent and clothing. It was in these times, of overcrowding and inflation, that ilha housing started to emerge.


Only very little is known about the exact origins of the ilha. They are thought to stem from the narrow medieval alleyways that can be found in the old city center of Oporto.3 The concept always remained a theme in the city, but found itself in an enormous revival during this period of scarcity on the cheap housing market. An initial reaction, filling up and dividing existing buildings into smaller and cheaper compartments, turned out to be a gross understatement of the problem: new housing was necessary and, as we will see, the ilhas seemed to be the only working solution. The concept seamlessly filled the needs of the new working class, combining not only economic, but also important locational, social and familial aspects of their lives.


In the above mentioned period of 1864 - 1900 more than 11.000 ilhas were built in 1050 plots. Half of them originated from the twelve year period between 1878 and 1890. Of all constructed houses in this thirty-six years, 63% were ilha dwellings. With an average above four persons per dwelling, 47.000 inhabitants were living in ilhas; nearly one third of the city (see graph 1 &2).


3.2 Legal Context

The ruling legal system turned out to be an important aggregator of the ilha development. Although 19th century Portugal did not have any advanced housing policy, two laws formed an ideal precondition for the concept.

The first law stems from right after the civil war (also known as the “liberal wars”, 832-1834), when large areas of land were disowned from the old aristocratic regime and church, in order to be auctioned to the middle class. A new group of (private) landowners arose, having a great influence on the development of Oporto throughout the 19th century.


As a side note, this privatization of grounds also formed an important cause of the before mentioned problems in agriculture. Before the civil war, grounds belonged to the community. Suddenly, these came into the ownership of a new elite, bringing all kinds of new difficulties to the rural system.


An important new tool for these landowners was the “Civil Code of 1867”. It allowed for a subdivision of ground based on a chain of hierarchically successive leasings: the direct landowners leased (parts of) their ground to sub lessees. They, in their part, had sub-lessees, which sometimes had sub-sub-lessees, and so forth. The lower one was in the chain, the lower ones status in society, and the closer one was to the actual construction of the ilhas.


The second important legal precondition is the “Municipal Code of Postures”, dating from 1869. This legislature basically allowed for anything to be built inside of building blocks, as long as it wasn’t visible for the public. The review of the city council was only needed for buildings facing the street; everything else was not subject to local control.7


The two rules played an important role in the structuring of Portuguese society. Also, they formed a firm basis for the building of the ilhas.


3.3 Developer

Oporto’s growth was largely governed by the before mentioned new class of land owners Urban renewal and expansion divided the city into larger, less organic, segments that formed the basis for further growth. Older and more organically formed streets were widened or extended and new roads and bridges were built according to more rational planning principles.8 This new segmentation led to the introduction of the building block in the city of Oporto, where inhabitants could buy a plot to build their houses. The average parcel was 5,5 meters wide and up to a 100 meters deep.


It was the lower middle-class that found themselves in the possession of these plots of land, but nonetheless in economic troubles. Amongst them were merchants, shopkeepers, traders and starting industrialists. They were the ones that initially started to build the ilhas; filling a gap in the market by helping the very poor, but in the mean time making their own lives a little more bearable. The mutual benefit was of great importance for the survival of the ilha concept.


History has proven this fact, since richer developers (mostly industrialists) hardly ever succeeded in building effective ilha housing. The ilhas they built fitted to their own scale of investment and stretched out over larger areas of unbuilt land. Although they were of better quality, connected to sewage, bigger (sometimes even multi story dwelling; the before mentioned “ilhas verticais”),and so forth, these kinds of projects hardly ever succeeded, since they were built to yield bigger profits. The working class could not pay these rents, so the projects often failed.  They were leased by lower middle-class families, used as a collective dwelling, or divided into smaller bits. Generally taken, it was not a good investment. Besides from that, most rich industrialists had no problems whatsoever with the cheaper forms of ilha housing: it allowed them to keep the workers wages low.


For the lower parts of society however, the building of ilhas did yield profits. Small size, poor construction, and a sober layout kept required investments low. Maintenance costs were virtually absent. The rent approximated ten to twenty-five percent of the market value, amortizing the invested capital in four to ten years. The building of the ilha tended to proceed slowly over multiple years, according to the availability of means. The returns were fast but small: a logical result of the small investments made.  However, for the people building the ilha, the profits were adequate.


3..4 Scattered Locations

Different types of ilhas were built at different places throughout Oporto, but most of them are found in a ring surrounding the 18th century expansions. As noted before, two types of dwellings existed: ilhas built in already established parts of the city (dating from the first half of the 19th century) and ilhas built in areas that were still empty in the second half of the century.


The first option is by far the most common: ilhas built on the inside of urban blocks, in the back gardens of former middle-class houses, where the advantages of the Civil Code applied. They were hidden from the eye; in contrast to the (less common) second case, where neighborhoods irradiated a distinctive working class character. These were mainly found in the surroundings of industrial quarters.


In both cases, the emergence of ilhas is related to a fall in demand for middle-class housing in certain areas. Whether this was due to unfavorable topography, the rise of industrial expansion nearby, the vicinity of other working class areas, or due to the aging of the existing population, middle-class families moved to newer (better) parts of town. As housing prices dropped the conditions for lower priced (ilha) dwellings were created, resulting in the colonization of the area by low income households.


In the maps on the following pages locations with a high number of ilhas is displayed by the black circles, projected on the development of Oporto during the 19th century.


3.5 Conclusion

The preconditions that caused the ilhas to exist can be seen as a result of several historical and socio-economic events, including the genesis of the countryside, industrialization, an oversaturated labour market, the decay of several middle class districts and the profitability of sub-leasing for lower-middle-class incomes.  It is probably safe to say that, in 19th century Oporto, the building of the ilha dwellings was the only thinkable solution to the overcrowding of the city: larger and better housing projects were too expensive for the working middle class. An answer to the problem is found in mutual benefits. Only lower middle class families were able to benefit from the very little money that could be made from housing that was cheap enough for the working-class immigrants.



4. Ilha inhabitants

By Robin Verstappen


Industrialization is often associated with the breakdown of the extended family into smaller nuclear, or simple, families. Although different kinds of people link this phenomenon to different kinds of moral and social values, the ilhas, while heavily criticized by Portuguese society for the lack of those values, form an interesting example of a continued importance of the extended family in an industrial society. The full extent of the family was a necessary condition for survival.


4.1 Cottage industry

By 1880, about one third of Oporto’s inhabitants were employed in industry. However, as shortly mentioned before, industrialization in Portugal never became very advanced: there were hardly any modern factories. A very large amount of the working population (34%) was active in the textile sector; a kind of industry that needed very little technological training and was able to thrive on the cheap and abundant labour available in Oporto. Around 1880, about 10.000 looms were operated in the cotton weaving industry, most of which still worked by hand. Hence, a very large part of cotton production did not come from factories: only three large steam powered factories are known, containing a total of 256 looms.


The bulk of the production came from smaller (manual) looms located near, but mostly within, the workers homes. They were still the property of “factory” owners, who could possess up to 800 looms throughout the city. Labourers, although working at home, were still reliant on the factory, which they only visited when he or she handed in the produced cloths for the money agreed upon. Training was of no worry for the industrialist: that too happened within the family. Workers had to teach their women and children themselves in order to survive on the little money that could be made.


The system was cheap, hardly required any investments and labour was abundant. One could say that, due to the continued use of traditional production techniques, factory owners could make greater profits out of smaller investments than in the case where modern equipment was used.


4.2 Public opinion

In the 1880’s the authorities woke up to the housing problem. This was not due to any specific demand: those who lived in the ilhas were never used to anything better. The desire to new housing solutions usually rose from the richer parts of society, although one could doubt their true intentions. Earlier we already noted how the more advanced building projects for the poor often failed because of their profitability: something should be done, but only if money could be made. Regrettably, the problem goes further than this and even touches the moral standards the inhabitants of ilhas were thought to have.


Authorities and educated classes saw the problem in a pathological character: the ilhas were dirty places hidden inside city blocks, forming a threat of disease and infection. Around the turn of the century, there was a mortality rate of 31 deaths per 1000 inhabitants per year1, mostly due to cholera, bubonic plague and tuberculosis. In a more popular image, this lack of hygiene was easily linked to the moral standards and family values of ilha inhabitants: they were considered as lesser people, being savage and hostile.


A common mechanism in any society is to associate spatial location with class: there are always “good and bad” neighborhoods. Oporto, however, was going through a period of rapid change and was in lack of such mechanisms. For a long time, the mediaeval city walls established a difference between inner and outer city. This difference was not only spatial, but was linked to social and moral differences as well. Outsiders were considered to be dangerous and strange. 2

When the city walls were breached and urban renewal started to change the morphology and characteristic of Oporto, these rules dissolved. New distinctions had to be made, this time being based on hygiene. In this mode of thinking the dirty ilhas were easily seen as a scapegoat for all that was negative about the city, inevitably linking this with the inhabitants’ moral standards. As ironic twist to this story is that, before the ilhas went mainstream, already a lot of poor people’s houses were demolished due to sanitary reasons. This too was a cause for the housing shortage which led to the building of more ilhas.


The invisibility of the ilha evoked mixed feelings: it was seen as good and bad at the same time. What was hidden was hard to control and understand, but also not that much of a bother in daily life. It led to an easy exclusion of the ilha from what was considered to be the “real city”; something still echoing through modern day Oporto.


4.3 Family Habits

Of course this popular image was highly exaggerated. Nonetheless, as in any growing city, disease and infection were a constant threat. Around 1880 the problems started to get out of hand: constant outbreaks of cholera led to great fear in society. Of course this didn’t improve the image of the ilha any further, nor did it result in any (fast) improvements. As a positive consequence, it did lead to more sociological and medical research in the city. This makes it easier for present researchers to study the situation.


Statistical analysis uncovers some remarkable differences between the ilha inhabitants and the rest of the city. Inhabitants were generally younger and had a higher sex ratio than the rest of the city (84% versus 73%), although females outnumbered males everywhere in Oporto. Due to this imbalance on the marriage market, especially younger, independent women found themselves forced to live in the ilhas. Between the ages of 30 and 50 however, more (working class) men are found, only to diminish soon after the age of 50, due to the large mortality rate in the male parts of society. As a consequence, many widows had to move to an ilha in order to survive financially.

Further analysis by age shows remarkable gaps between certain age groups: young children (0-14) and adults (30-45) are over overrepresented, just as certain groups above 55. Consequently, the ilhas appear to form an important means of survival for families in a critical phase of their lives: young families with children who were still unable to work, and seniors without a partner.


The inhabitants of the ilha left home early in order to earn their own income. This led them to find a partner and marry on quite a young age: between the age of 20 and 25, 55% was already living together, opposed to 25% in other parts of the city. However, this early marriage was not just voluntary: the organization of domestic labor and the complementary economic roles of males and females were quite pressing factors to form a couple. Very often, these couples would remain unmarried; a tendency that hardly improved the negative public image.


According to statistical data families in the ilha remained rather small (3.3 persons compared to 4.3 elsewhere): a logical consequence of the small area of the dwelling. However, it should be noted that ilha housing made it quite easy for relatives to live near one another, creating circumstances as seen in extended family dwellings. A systematic research of this thesis is fairly difficult in a city like 19th century Oporto, but case studies have been made to support this theory. The tracking of name lists and civil records has shown neighbors often being relatives and married sons and daughters living in the same ilha as their parents.


Illustrated below is a schematic view of family relations within a former ilha near “Rua da Saudade” in Oporto. In eleven houses three “extended families” could be found, having familial relations between the different dwellings in the ilha. These kind of “family groups” usually consisted of brothers and sisters who remained close to each other after leaving the parental house. Extended families not only worked together internally, but also outside of the family, forming workgroups with other families in the ilha in order to help and support each other for mutual benefits. In 1881 two of the houses in the before mentioned ilha were shortly converted into a factory which was used collectively by all present families.


Of course this collaboration between family members and neighbors was preceded by a detailed division of tasks within the (simple) family itself. This was accompanied by a great dynamics in the family structure: when the market was favorable and the domestic workgroup’s capacity rose, family members from out of town would be brought into the house to help with production, look after the kids or assist in some basic household tasks. When the economy turned, workgroups would be reduced to a bare minimum, leaving just the essential elements intact.


As said before: living in an ilha often corresponds to critical phases in the life of the inhabitants. Usually this occurred when a couple’s children were unable to work, or left home and got married. When children grew up, they had to learn to earn an income quite fast, so they could support their parents. When they moved out they had to form a new workgroup of their own in order to survive. Often the (empty-nest) parents were tied to this new group: both sides could use the extra help and security this brought upon them.


The high adaptability of the simplistic ilha dwelling fitted perfectly with the fast and dynamic changes in and between families. Advanced tactics in “space management” led to shared facilities, easy to alter interiors and other forms of spatial behaviour that was heavily related to certain survival strategies performed by an ilha community. However, the ilhas left little room for privacy. This resulted in the development of certain ilha-specific sayings, gestures, tastes, etc. This strong cohesion inside of the group often led to suspicion of strangers: not everyone was allowed to live inside the ilha. Mostly only known immigrants (friends and family) were allowed, making the ilhas also a space of urban integration.


4.4 Conclusion

Research at different places brings comparable results, revealing a situation quite different from the prevalent theories about family breakdown in industrialized societies. At first sight the ilhas did have less complex families (12%, versus 23% elsewhere), but taken into account the family ties within the ilhas themselves, this number is far greater than people were led to believe.


This renders the popular image of the ilha inhabitant, as being in lack of moral and familial values, as completely incorrect. Social ties were often stronger and more complex than in middle- or upper-class households: they tended to live in much more secluded environments, turned away from the city centre, and had more formal family relations. In the opposite, two thirds of the ilha inhabitants had daily contact with cousins, uncles, aunts and other distant relatives. Even those who did live alone, far away from their families, were in close social networks with their neighbors, used to travel to their family in the weekends and share income with them. People relied on each other in order to survive. These strong social ties are one of the main reasons the ilhas are still inhabited in present times.



5. The Ilha through the ages

By Vincent Willems


Above we have seen how the ilha dwelling formed an essential part of 19th century Oporto, functioning as a simple solution to a diverse and complex problem. The typology remained dominant for a long time, especially when, in the last years of the 19th century, further industrial mechanization caused even harsher economic conditions. By this time poverty reached such amounts that ilhas were also inhabited by other types of workers: only 68% was working in industry, the rest consisted of commercial and service workers, including: police, soldiers, small businessmen, shoemakers, carpenters, masons, laundresses and street vendors.1


Although in 1900 new rules banned the building of ilhas, they continued to be built illegally. It took until 1930 before the first ilhas were to be demolished. In those days there were around 1300 ilhas left, corresponding to 14,676 homes. In 2001 8465 homes remain to exist, located in  1168 ilha units.


It appears that   the number of ilhas decreased only very slowly from 1900 onwards. This does not correspond to the number of ilhas that are said to be demolished. No exact explanation is given; statistics could be wrong, new ilhas could be discovered and the annexation of small neighbouring cities (that also contained ilhas) formed a cause for troubled statistics regarding the ilhas.



It appears that   the number of ilhas stayed the same from 1900 onwards. However the literature would suggest that from the 1930’s numerous ilhas have been destroyed. This could be explained in two ways; or the statistics are wrong or the annexation of small neighbouring cities that also contained ilhas was the cause for a more or less constant number of ilhas.


5.1 Legal systems and expansion plans

The analysis of the evolving role of land-use planning in the construction of Portuguese cities from the second half of the nineteenth century onwards cannot be dissociated from the evolution of the national political system. As explained, the country went from a constitutional monarchy towards a republic in 1910, submerging afterwards, by 1926, into a dictatorship that lasted for fifty years, and emerging, in 1974, as a parliamentary democracy. Beyond the different social, economic and cultural implications associated with each of these political regimes, their conceptions of urban planning are substantially different and gave rise to a number of specific types of planning documents: General Improvements Plan (Plano Geral de Melhoramentos – PGM) from the constitutional monarchy, the General Urban Development Plan (Plano Geral de Urbanização – PGU) from the dictatorship regime, and the Municipal Master Plan (Plano Director Municipal – PDM) from the democratic regime.


In 1865, the government introduced the PGMs. These plans required the identification of the existing streets, squares, gardens and buildings, as well as the construction of new urban forms, according to new sanitary standards and enhanced aesthetics to accommodate more comfortable housing and public transit facilities. Each of these plans would be elaborated by a four-person Commission composed of an engineer and an architect employed by the Public Works Service, an engineer appointed by the City Council and a member of the Board of Public Health of the Kingdom. Until 1934, the year the new PGUs replaced the PGMs, these were the documents that guided the preparation of several sectoral and territorial studies on Porto as well as on other Portuguese towns, which led to the first wave of statutory urban plans.


In 1934 the PGU was introduced by a national decree. This legislation was influenced by the first French urban legislation – the Cornudet law – and focused on a wider range of organizational and procedural subjects. If the urban reconstruction of the post-war period was the driving force of the French legislation, the need for a broader programme of urban improvements was the motivation for the Portuguese legislation. According to this decree, all the city councils from the mainland of Portugal and the Atlantic Islands were bound to produce topographic maps to support the subsequent preparation of PGUs. These plans were expected to guide the physical expansion and consolidation of the Portuguese cities, according to the particular demands of economic and social life, aesthetics, public health and traffic, and with the maximum advantage and commodity for its inhabitants. The PGU should then comprise: a general plan, a presentation plan, a working plan, an urbanization plan, the general schemes of the drainage system, the water supply system, the street lighting, the transport networks, some longitudinal and cross-sections of the main streets and a text justifying the adopted methods and policy options.


The PDM was introduced in 1982 and changed in the early 1990s. The PDM should then establish the spatial structure for the whole municipal territory, the general land-use classification and the urban boundaries and urban indicators. It should translate the municipal development objectives, the rational distribution of economic activities, residential needs, public services and facilities, communication and transportation networks and urban infrastructures. The municipal plan was composed of: a regulatory code, a zoning plan defining the different classes of space according to the dominant use and the priority areas for operational planning and management, and the rights of way and planning restrictions.


5.2 Structuring forces

Under the long-lasting dictatorship installed in 1933, the political regime and public administration in Portugal were extremely centralized. Circumscribed by the technocratic legitimacy of the central state, municipalities did not have political or financial autonomy, their technical self-sufficiency was also strongly restricted as most plans were prepared in Lisbon.


When, in the 1940s, planning began to be understood as a relevant branch of public policy, the rationale was to control and direct the process of urbanization that was following the strong migratory movements in the country. This was also the leading principle under the profound modifications in planning’s legal framework that occurred between 1970 and 1973. The main concern was then with the preparation of plans for urban areas (rather than for the whole municipality) and the focus of planning was on land use change and urban form (including zoning).


However, a hefty and inefficient system operated by a restricted and an intellectually, socially and physically detached universe of planners, meant that very few plans were approved until the mid-1970s. Planning was a deterministic instrument used by central government to rationalize physical interventions in urban areas through the implementation of detailed blueprints for the future form of cities. As is argued by many, this conceptual framework remains omnipresent in Portuguese contemporary planning.


In fact, despite the radical transformations that the democratic revolution of 1974 and succeeding EU membership brought about in the context of planning, the pace of change of its dominant approaches has been tremendously slow. The socially pervasive conceptual framework inherited from the long years of dictatorship is still rather influential on professional, social (and political) perceptions of the nature and scope of spatial planning. This means that, despite significant changes, the most distinctive and structural characteristics of the planning system remain active. The rational comprehensive approach that dominated before 1974 is still acting as the main structuring force in the contemporary form of the planning system.



5.3 Foundational endeavors

With decentralization and the reinforcement of local power on the agenda, the new democratic regime provided municipalities with political and financial autonomy, legitimizing democratic decision making at the local level. After an initial preoccupation with the provision of basic services, the contemporary character of the planning system started to take shape at the beginning of the 1980s, with the introduction of a set of legislative instruments aimed at regulating state intervention in spatial planning, particularly the PDM, a land use regulatory plan based on functional zoning.


Prepared and approved by local authorities (but still ratified by the central government), these plans brought three main conceptual innovations: first, they covered the whole municipality rather than only the urban areas; second, an explicit socio-economic strategy underpinning land use and zoning proposals was required; and third, despite its weakness, a system of public participation in plan preparation and approval was introduced. In what concerns the architecture of the system as a whole, a division between physical local plans, under the responsibility of local authorities, and regional and special plans, under the responsibility of the central government, started to get defined.


However, procedures were cumbersome and most local authorities were technically ill-equipped to prepare plans. As a result, only four out of 305 municipalities had their PDMs approved and ratified by the end of the decade. This led, at the beginning of the 1990s, to the simplification of technical requirements and approval procedures as well as the introduction of penalties for municipalities that failed to prepare their plans.


The European Union’s Community Support Frameworks were the main force behind the redrawing of the system, and the focus on physical infrastructures of the first two of these frameworks meant that the emphasis on land use regulation and transformation throughout zoning mechanisms was maintained. Moreover, consolidating the hierarchical relationship (in terms of scale and detail) between the different types of physical local plans existing at the time (since then called PMOTs—Municipal Plans for Spatial Planning), the renewed legislation was also clearer about the architecture of the system at the municipal scale. Nevertheless, it was not until the end of the decade that a distinction in terms of principles and objectives was made between the different categories of plans.


5.4 Conclusion

Urban planners from the beginning of  the 20th century till now had to deal with a variety of problems in often changing political conditions. Therefore the demolishing of the ilhas has been on the agenda for a long time, but among many other themes. An alternative for its inhabitants has not been yet been given, so the ilhas are still in use up until this day.


Being long disregarded, chances for the ilhas to be appraised and preserved do not grow with time. Not so much their physical state has deteriorated beyond a point of no return, but more the image and status within society. Adaptation to the modern economic, social and ecological conditions could be a last chance for the ilhas to survive, but will be a great challenge to achieve, not for urban planners only.

Main Source

Fátima Loureiro de Matos & Rosa Maria Veloso Vieira Rodrigues (2009). As ilhas do Porto: Lugares de Resistência (Oporto). Revista Eletrônica de Geografia, v.1, n.1, p.33-57. Rio Claro, Brazil.



1) Journal de Noticias (02-06-2008) Ilhas de afectos preservam espírito comunitário. Retrieved 04-08-2010.


2/3) Satelite images property of Google. © 2010 Google, © 2010 Digital Globe, Geo Eye, Cnes/Spot Image, IGP/DGRF. Fair use for academic purposes.


4) Journal de Noticias (02-06-2008) Ilhas de afectos preservam espírito comunitário. Retrieved 04-08-2010.


Graphs in this chapter are remade according to the data from Fátima Loureiro de Matos & Rosa Maria Veloso Vieira Rodrigues (2009). As ilhas do Porto: Lugares de Resistência (Oporto). Revista Eletrônica de Geografia, v.1, n.1, p.33-57. Rio Claro, Brazil.


6. Present times

By Robin Verstappen


In present times, people are still living in the ilhas. Most of the houses have not changed a lot, still lacking basic hygienic facilities and the comforts of a modern day home. The reasons for their ongoing existence are manifold, originating from a mix of bad policy, neglect, romanticism and poverty. Ilhas remain cheap: 70% are rented, 65% are costing less than 25€, and 23% more than 100€.


Nowadays the ilhas turned out to be a great safe haven for (illegal) immigrants. However, a lot of the inhabitants are still Portuguese and often inherited the property from their parents. Occupations remained remarkably comparable to the situation of 1910: around 40% is working in industry and commerce, 24% are craftsmen and 15% are small salesmen and service workers. In 2003 there were 1130 ilhas left, containing 7650 houses. (1)


6.1 Ramalde casestudy

In 2008 a research was performed in the industrial district of Ramalde. Having an advantageous position in the city, near important roads and railways deployed in the end of the 18th century, industry has been a dominant factor for a long time. Consequently, so were the ilhas.


Due to several large city plans, formed around the 1950’s, the area was transformed in to a more modern industrial terrain. A new zoning law appointed Ramalde as industrial core, in order to relocate industry from other parts of Oporto. Large scale social housing was deployed and ilhas were to be eradicated. The applied policy was exceptionally strict and successful, transforming the parish of Ramalde into the only part of Oporto which still grows in population.


Before these new developments, Ramalde was a true core of ilha dwellings. Of course, some of them still remain to exist in the surroundings and adjacent districts of the area. Three “hot-spots” can be found, containing about 300 ilha homes out of the 770 that could be found throughout the entire area. In 2007, 130 of these households were surveyed.


The largest cluster was found to be of fairly good quality, mostly due to the work of inhabitants. Although many of them still had modest toilet facilities, they were reasonably well preserved; sometimes even a second storey had been added. This resulted in slightly higher rents in this neighborhood (around €200). Within the cluster, 24% of the surveyed homes had a toilet outside of the dwelling, with hot water; 25% without. Only 29% had an indoor toilet with hot water (3% without), and 10% had collective facilities. These standards are still very low, although they are quite high for the ilhas left in Oporto.

Around 28% of the inhabitants had been living in the ilha for more than 50 years (see graph), causing strong social relations between neighbors. This can be seen as positive for the senior inhabitants: loneliness, often associated with old age, is nearly absent. Another large share (40%) has lived in the Ilha for 0-10 years, those people often being fairly young. Apparently this particular ilha forms an interesting investment for starters on the housing market of Oporto.


Within the population, a strong relation between age and provenance was found. Elder people were often from Oporto itself, or from the rural areas surrounding it. Younger inhabitants were more often foreign immigrants, coming from Brazil and Eastern Europe (30%). On the degree of satisfaction, the majority of respondents liked the centrality (20%), the affective ties (19%) and the silence (17%). In negative aspects, 42% complained about the poor quality of housing, and 26% about conflicts with the neighborhood.


In the other two nuclei the researchers noted some differences. Core two was of lesser quality: 38% of the houses were degraded because the tenants were too old and the landlord didn’t do any work. In return, these houses had lower rents. Half of the dwellings had their own toilets, 37% had a toilet outside and 13% had collective bathing facilities. This relatively “high” score is mainly the result of the ilha being quite irregular compared to the standard layout. The shape is more organic, dwellings differ from the standard type and have been replaced or added in more recent years.


Retirees (35%) and unemployed (22%) made up 57% of the ilha, revealing a large and vulnerable group of civilians. The inhabitants mostly value the same things, but 33% claimed not to like anything at all about the ilha. This group corresponded to the unemployed, or those living in the ilha due to other problems (such as divorce). They tended to live in the most deteriorated houses of the area; a forced situation, not at all stimulating a romantic view of their housing condition. 54% would like to move, but remain in the same neighborhood. The rest, a group corresponding to the elder inhabitants, wanted to stay.


In the third cluster the research found more active landlords. Here nearly 72% had a toilet inside of the house and no collective facilities were found. This is mainly seen as a result of a fast turnover of tenants. Here, far less people were unemployed (14%) and 77% was born inside of Portugal. However, opposed to cluster one, in this case also those younger than 65. Here nearly 47% liked the bonds of affection and 31% liked the internal yard that was located within the cluster. In negative terms, 87% mentioned the bad housing conditions.


6.2 Three groups

In total, 270 residents were interviewed. As has been illustrated above, no ilha seems to be the same. By further statistical analysis, the researchers found three groups of inhabitants, whose characteristics are linked to the age group one belongs to.


The first dominant group is the elder population. They are not very well educated, can only read and write, and come from Portugal, although not from Oporto itself. Within this group, two realities exist. Some are better off financially, and own homes that provide good living conditions. Another part of this age group is not as well endowed and lives in less comfortable ilhas. They are more dependent on their incomes and are not able to keep their ilhas in a very good condition. Nevertheless, most of the elderly want to stay: they have too many memories of the place, and close ties to the neighbors, keeping loneliness at bay.


The second group is aged between 46 and 64. They are slightly better educated (primary or secondary school) and have good relations with the previous group, often being family in one way or another. The largest part of this group is born in Oporto itself and is unemployed or retired. If one is working at all, it remains precarious. Although the group is smaller and less representative for the ilha compared to other two, it interacts with the community in an affectionate way, being strongly tied to the ilha, not having any desire to leave.


The third group is the working class, and interacts with the community in a lesser extent. They behave different, as if don’t really belong in the place, hoping to move on soon. Most of them succeed in this, leaving within a short time.


Consequently, they hardly ever become a real part of the ilha: the previous groups see them as intruders. To aggravate this, a large share of this third group consists of foreign immigrants, coming from Brazil, Eastern Europe and PALOP (Portuguese speaking African countries). Often, these immigrants are illegal: for them the ilhas form a perfect hiding place. This ethnicity brings cultural and lingual differences that complicate the situation even further, forming an extra barrier between this group and the more rooted inhabitants.


6.3 Conclusion

Although the ilhas are still a place of poverty and (by the state) remain to be seen as places that need to be demolished, the Portuguese newspaper “Journal de Notícias” headlines “Ilhas preserve community spirit”4. In interviews, inhabitants speak about their ilhas in positive terms: they see the ilha as their greatest asset and treat their neighbors as family. Many of them see the ilha’s corridor as a shared living room/garden, boosting the community spirit. Although conditions can be harsh, they want to stay where they are, thwarting demolition plans.


One could say that the ilhas are misunderstood by the government, that the problem asks for a different solution. If you look at the ilhas through the glasses of the past and see them as a dirty and morally degraded element in the city, eradication seems as the only possible solution. However, ilhas also have the power to be seen as a place with potential: they form a great example of densification, can be an opportunity for those who are unsatisfied with standardized modern housing, the sheltered open space forms a great place for children to play and creates porosity in the fabric of the city. A more modern and understanding look at the problem may be a great alternative for the (often failed) attempts to demolish the ilha, and can also be a solution for the housing problem Oporto still has.


7. Similarities to other types of housing

By Alke van den Berg


In the literature that is written about the ilhas of Oporto the similarity between the Portuguese ilhas and the British back-to-back houses is often pointed out, although never explained. Also there exists a clear relationship with the so-called cortiços of Rio de Janeiro which Manuel Teixeira covers in depth in one of his publications. There will now follow a comparison between these two typologies and the ilhas to place the typology in the bigger picture of worldwide housing development in the 19th century.


7.1 The cortiços of Rio de Janeiro

The parallels between the cortiços of Rio de Janeiro, that were built in great numbers at the end of the 19th century, and the ilhas of Oporto are many. In short they share the same socio-economical circumstances, type of developer, process of development  and form and location of the buildings.


The cortiços consisted of small, often single roomed, houses that were built in rows on either one or two sides of a yard or corridor and could contain one or two storeys. The access to the upper level consisted of steep staircases and narrow wooden galleries. As in Oporto, the parcels of land in Rio were narrow but deep. As is clear, this description could also be given for the ilhas. However the living conditions in Rio  could be far worse. The areas covered by a cortiço dwelling could be as low as three square metres. Sometimes the houses would be partitioned as the ilhas were, but most of the times they would just be made up of one room with place for one door and one window, since the frontage was only three metres wide. Exceptional cases have been known where the width would be reduced to two metres and the depth to just a single metre.


As in the ilhas, the lavatories were shared by all inhabitants and were usually located at the end of the yards. On average a lavatory was shared by ten or twenty houses. There was no sewer system and most cortiços used cesspools. Water supply was done by public fountains that either were located within or outside the complexes. Since the dwellings could be very small other sevices, like kitchens, could also become public. This ensured that the yard would become the focal point of life in the cortiço and it was often used as a working place as well. The inhabitants of the cortiços consisted of the lower classes; the poor just as in Oporto.


Teixeira deduces from the great number of small cortiços scattered through the city that they were the result of many small-scale developments by small capital. Most owners of the cortiços were small trades men (retail traders and shop keepers e.g.), who invested their savings in the construction of these dwellings. They would often develop a cortiço by one or a few houses at a time, so the profit of each stage would finance the next. As in Oporto the land on which the cortiços were built wasn’t owned by these developers but by large land owners, who would devide their land into smaller pieces and let it to other people, that were lower on the social ladder.


Investing in the cortiços was very profitable. The objective of the owners was very simple: invest as little as and get as much profit as possible. This meant that the cortiços were built with high intensity land use, inferior building materials (wood or masonry) and crude construction techniques. The objective would lead to interests from fifty percent up to one hundred percent on the capital invested. This was a lot higher than the usual interest rate at the time of twelve percent. The greedy objective resulted in reduced dimensions, poor construction and overall fragility of the houses, the poor living conditions and the health issues of the cortiços.


The owner of a cortiço, who would often live inside or nearby, would most of the time personally manage the complex. A common situation was that of a grocer or another type of small shopkeeper, that lived above his store, would exploit a few houses built in his backyard. The shop would face the street and control the acces to the cortiço behind it. The tenants were supposed to be frequent customers of their landlords shop.


The similarities between the ilhas and the cortiços can be explained by the great number of Portuguese immigrants that arrived and lived in Rio in the nineteenth century. Oporto was the main point of departure to Brasil for almost half of the total number of Portuguese immigrants in the nineteenth century. The main port of arrival was Rio de Janeiro, which tells us that there existed a strong bond between these two cities. It is therefore safe to assume that the Portugese immigrants brought with them the typology of the ilha and applied it, albeit with some adaptations to the new environment. This is backed up by the fact that half of the cortiços that existed in 1879 were owned by Portuguese. In 1890 the estimates show that 20% to 25% of the total population of Rio lived in cortiços. That amounts to 100.000 or 125.000 people. Of course the typology wouldn’t have been such a success in Rio if the socio-economical circumstances hadn’t been comparable.

In the last decades of the 19th century the economy of Brazil transformed from a mercantile-exporting, slave based, economy to industrial capitalism. A crisis in the coffee plantations around Rio de Janeiro caused a large migration to the city of the rural population. Added to these local emigrants were the emigrants from the Old World. The development of industry in the city, the growth of the population and the investment of mercantile capital in urban activities were the basis for urban growth in Rio. In 1906 the size of the population had become 811.443 of whom 24,8% were foreign emigrants. Amongst these emigrants were a lot of people looking for new and better lives.


The lower class, which consisted for a large part out of the emigrants, had very little money to spend and the cortiços were the only type of housing they could (hardly) afford. Therefore more or less the same circumstances existed in Rio de Janeiro as in Oporto, although stemming from (slightly) different causes. This explains the success of the copying of the properties of the ilhas in the cortiços.


7.2 The back-to-back housing of England

At the end of the 18th and beginning of the 19th century the rural workers from the small villages all over England were attracted to the big cities. They were looking for work and better lives and thought they could find them there. The cities were undergoing major transformations at the time because of the Industrial Revolution that was raging through England. The new industry needed a lot of labourers, so the rural emigrants indeed found work in the cities. However a better life is a different story. The labour in the factories payed very little and to cope with the rapid growth of the populations of the big cities the back-toback housing was developed; relatively cheap houses for the working class.


The back-to-back houses consisted of two or three storeys, that each contained one room, so per house there would be two or three rooms. The typology is called back-to-back because the houses would share three walls with other houses, so they would stand with the backs of the houses against each other. Because of this the back-to-backs were notoriously ill-lit, poorly ventilated and sanitation was of a poor standard. The ground level would often be the kitchen and the higher storeys bedrooms. However, the families that lived in the houses were large, sometimes consisting of twelve people. The houses would often be build around a courtyard, where the communal washing- and sanitary facilities would be located, that on average would be shared by twelve families.  Often the inhabitants would take in lodgers to supplement their meager wages. They would have to share their room with the lodger, guarding their privacy with nothing more than a simple curtain.


The back-to-back housing was very common in the Victorian city and could be found in cities as  Leeds, Manchester, Salford, Liverpool, Bradford, Nottingham and Birmingham. They would be build up until the 1930’s when it was decided that housing quality should be of higher standards since the areas of this type of housing had become slums a long time before that. In the 1920’s though, at the initiative of council housing, programmes of slums clearances had been initiated, which caused mass demolishment of the back-to-back housing. In the 1970’s only very little back-to-back housing still existed.


The shared characteristics of the ilhas of Oporto and the British back-to-back housing are the socio-economic circumstances under which they developed, the inhabitants and some of their physical aspects. Both were developed for the new poor lower class immigrants from the rural areas of the country, that came to find better lives in the cities in great numbers. Both were built in such a way, that they were as cheap as possible: they shared most of their walls with other houses, only had openings in their faces on one side, had shared facilities with many other houses and were made of inferior material.


7.3 Conclusion

When looking at the ilhas from a worldwide perspective, one can place the ilha in a series of housing typologies that came into existence as an answer to the new circumstances that the Industrial Revolution created for the lower classes. Though the precise circumstances may differ from place to place, for example the culture, climate  or the type of industry  of a city or country, the overall similarities, in form, inhabitants and living conditions can clearly be traced back to the migration of large groups of poor emigrants, either from the countryside or abroad, to the cities in search of work in the (modern) industry.