Palace of Culture and Science (PKiN) is the highest building in Poland, and is located on Defilad Square in the center of Warsaw. It was erected as a gift of the Soviet Nation for the Polish Nation. It was opened in 1955. It was built in three years according to a project of a Russian architect Lew Rudniew and inspired with Moscow skyscrapers which on the other hand were inspired with American art deco skyscrapers. It is a mix of socialist realism and Polish historism. Currently, it is a house of many companies and public institutions, such as: cinema, theatres, bookstore, sport clubs, univeristies (e.g. Collegium Civitas), scientific associations and management of the Polish Academy of Science.