Industrialisation opened up unimagined possibilities for architects and engineers with the continuously improved materials of iron and concrete. At the same time, it revolutionised housing construction because more and more workers and job seekers were looking for a roof over their heads in expanding industrial regions.

In the beginning, there was still room for utopias. As one of the first entrepreneurs, the Briton Robert Owen carried out social reforms in his spinning mill in New Lanark around 1800 and conceived an ideal city for the workforce in the Renaissance tradition, but failed to realise it. More successful was Titus Salt, also a textile manufacturer, who had the "Saltaire" settlement built for his employees in West Yorkshire in 1851.

In France, Charles Fourier had developed similar ideas for production and living communities. Following his model, the factory owner Jean-Baptiste Godin realised the "Familistère" settlement next to his foundry in Guise in 1859: a ring of multi-storey residential buildings surrounds a wide courtyard with a glass roof that lets in a lot of light and serves as a communal space. Public facilities such as a school, kindergarten and shops are integrated into the complex.

The British urban planner Ebenezer Howard countered the uncontrolled growth of metropolises with the idea of the Garden City. Influenced by the American natural philosopher Ralph Waldo Emerson, he propagated small towns integrated into the landscape with detached houses and community facilities. Land was to be common property. The concept was implemented in Letchworth Garden City in Hertfordshire in 1903 and soon afterwards in Hampstead Garden Suburb in London.

Many 19th century entrepreneurs built flats because they felt responsible for "their" workers - they also hoped to retain qualified staff. For example, the factory owner Cristoforo Crespi, inspired by the idea of the garden city, built from 1878 a settlement with small workers' houses surrounded by greenery, a hospital, school and church, next to his cotton mill in Crespi d'Adda in northern Italy.

In Essen on the Ruhr, Alfred Krupp began building the first housing in 1855 right next to the smoking chimneys of his cast steel factory. In the rapid growth that followed, expanding factory facilities and further settlements eventually grew together to form a gigantic factory city, next to which the centuries-old Essen seemed like a village.

But soon paternalistic-minded entrepreneurs could no longer absorb the dramatically growing influx of workers. Hopelessly overpopulated slums sprang up in the urban centres, without clean water, effective ventilation or adequate sanitation. Diseases such as tuberculosis became rampant and the death rate skyrocketed.

An early attempt to house many people in a small area were the "back to backs" in the English Midlands: plain brick cottages, built in pairs "back to back" so that there were windows only on one side. Far more efficient for investors, however, were the tenements that sprang up in Victorian times in the slums of British metropolises such as London, Glasgow and Edinburgh. A prime example of the new form of housing construction born of the greed for profit, however, is Berlin, which was flooded with job-seekers at the end of the 19th century: There, mighty five- and six-storey blocks of brick houses were built - in the inner courtyards, the builders squeezed up to six multi-storey "back houses". Several thousand people lived in such complexes, often four or five to a room with a kitchen - and they also had to sublet their beds for the time they were working.

It was not until after the First World War that Europe's governments, together with non-profit cooperatives, systematically tackled the massive housing shortage. In Great Britain they mainly built housing estates with single-family houses, in Germany blocks of flats, preferably in parallel rows with enough space between them so that each row of houses had enough light. They often included communal crèches, shops or laundries.

The communal idea was particularly expressed in the residential courtyards of 1920s "Red Vienna". The most famous of these was the Karl-Marx-Hof, a "proletarian residential palace" consisting of five-storey houses around a wide, green courtyard. Shops and kindergartens, sometimes even libraries and post offices were integrated into the castle-like courtyards. Striking, creatively designed housing estates were created by Dutch architects influenced by the artist group "De Stijl": Initially often made of traditional bricks and sometimes crowned by a turret, later also made of prefabricated concrete elements with individual, colour-accentuated façades, as in the garden city "Watergraafsmeer" near Amsterdam.

Unlike in industrial construction, the new materials and production techniques of the era did not find their way into residential construction on a large scale until the 1920s: the representatives of the "New Building" now used concrete and mass-produced building elements instead of bricks. In housing estates such as those built by Ernst May in "New Frankfurt" or Walter Gropius in Dessau-Törten, standardised houses were built with white façades and flat roofs in clear shapes. The aim was maximum functionality at low cost - even in the furnishings: many architects designed furniture according to the same principle. Margarete Schütte-Lihotzky created the first ergonomically planned fitted kitchen with the "Frankfurt Kitchen".

Standardisation, however, led to reforming aspects such as lighting and greening taking a back seat again. Thus, the influential "Bauhaus" founder Gropius, who adhered to the idea of the "residential community", advocated the construction of "large houses". This concept reached a high point in the work of the architect and artist Le Corbusier. He realised his idea of a "house city" in 1952 in the "Unités d'Habitation" in Marseille: a huge concrete block with more than 300 flats, into which a kind of street network and two storeys of shops were built. Although glaring deficiencies soon came to light, the complex had a strong influence on housing construction.

In the Soviet Union, the ideal of communal living was further developed into the concept of the "socialist city": simple but comfortable flats, lots of green space and shared recreational facilities were ultimately supposed to produce a "New Man". The concept was put into practice after the Second World War when numerous satellite towns were founded for the workers of the gigantic new industrial plants in the socialist states: for example in Magnitogorsk in Russia, Nowa Huta in Poland or Eisenhüttenstadt in the former GDR. But in the centrally controlled urban development, all that remained of the once emancipative ideal were mostly long rows of standardised apartment blocks, built of prefabricated wall panels in park-like grounds.