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Functionalism and modern architecture

Helsinki also features several buildings by Finnish architect Alvar Aalto, recognized as one of the pioneers of architectural functionalism. However, some of his works, such as the headquarters of the paper company Stora Enso and the concert venue Finlandia Hall, have been subject to divided opinions from the citizens.

Functionalist buildings in Helsinki by other architects include the Olympic Stadium, the Tennis Palace, the Rowing Stadium, the Swimming Stadium, the Velodrome, the Glass Palace, the Töölö Sports Hall, and Helsinki-Malmi Airport. The sports venues were built to serve the 1940 Helsinki Olympic Games; the games were initially cancelled due to the Second World War, but the venues fulfilled their purpose in the 1952 Olympic Games. Many of them are listed by DoCoMoMo as significant examples of modern architecture. The Olympic Stadium and Helsinki-Malmi Airport are also catalogued by the Finnish Heritage Agency as cultural-historical environments of national significance.

When Finland became heavily urbanized in the 1960s and 1970s, the district of Pihlajamäki, for example, was built in Helsinki for new residents, where for the first time in Finland, precast concrete was used on a large scale. Pikku Huopalahti, built in the 1980s and 1990s, has tried to get rid of a one-size-fits-all grid pattern, which means that its look is very organic and its streets are not repeated in the same way. Itäkeskus in Eastern Helsinki was the first regional center in the 1980s. Efforts have also been made to protect Helsinki in the late 20th century, and many old buildings have been renovated. Modern architecture is represented, for example, by the Museum of Contemporary Art Kiasma, which consists of two straight and curved-walled parts, though this style strongly divided the opinions from the citizens. Next to Kiasma is the glass-walled Sanomatalo (1999).

There have been many plans to build highrise buildings in Helsinki since the 1920s when architect Eliel Saarinen proposed the 85-meter-tall Kalevalatalo in 1921, but few tall buildings were built until the 21st century. In 1924 Oiva Kallio won Etu-Töölö competition with his plan (several 14- to 16-story buildings). A 32-story city hall was also proposed. Other plans of the 1930s included the 18-story "Kino" palace, a 17-story apartment building, and a 30-story Stockmann building were proposed but only the 70-meter-tall 14-story Hotel Torni was built. (Hotel Torni was the tallest high-rise in Finland until 1976, when the 83-meter-tall Neste headquarters were completed in Espoo; Helsinki had rejected the tower.) Twin 30-story buildings were proposed in Pasila in the 1970s but were rejected. In 1990 a planned 104-meter-tall tower for the Kone company was also cancelled.

Highrise construction only started in the beginning of the 21st century, when the city decided to allow the construction of skyscrapers. Highrises were first built in Kalasatama, a primarily-residential district built on a former container port. As of 2024, four residential towers have been completed: the 35-story, 282-apartment, 134-metre-tall (440 ft) Majakka in 2019 (which is the tallest building in Finland); the 32-story, 124-meter Loisto in 2021; the 31-story, 120-meter Lumo One in 2022; and the 24-story, 98-meter Visio in 2023. The 26-story, 111-meter-tall office building Horisontti is to be completed in 2025, and three further towers are to be built in the complex. Tall residential towers have also been built in the eastern district of Vuosaari: the 87-meter, 26-story Cirrus was completed in 2006, the 24-story, 85-meter-tall Hyperion was completed in 2023 and the 33-story, 288-apartment, 120-meter-tall Atlas is due to be completed in late 2024.

Skyscrapers have also be planned in the Pasila area, with a handful of over-100-meter-tall towers in various stages of planning or early construction as of 2024. In Jätkäsaari, a 113-meter-tall hotel and a 24-story residential tower have been approved. 121- and 93-meter-tall office buildings are planned to be built in Ruoholahti. Well over 200 high-rise buildings will be built in Helsinki in the 2020s.