The apartment building "Polska Akademia Nauk" (20 Wiejska Street, Warsaw, Poland) was inspired by Le Corbusier's principles. The architect was Jerzy Gieysztor and the building was completed in 1964. Among Central European countries, it is unique for its period. It is an abstract sculptural building that floats over pilotis (concrete piers). All its apartments are spacious, there is an indoor shopping mall, and the roof terrace has a swimming pool. This building was also inspired by the 1937 World Expo in Paris, especially the wall relief and the entrance roof. Other Polish buildings inspired by the Unité d'Habitation include the Za Żelazną Bramą Housing Estate (Behind the Iron Gate) in Warsaw, and Superjednostka in Katowice, built in the 1970s.