In February 1946, Lviv became a part of the Soviet Union. It is estimated that from 100,000 to 140,000 Poles were resettled from the city into the so-called Recovered Territories as a part of postwar population transfers, many of them to the area of newly acquired Wrocław, formerly the German city of Breslau. Many buildings in the old part of the city are examples of Polish architecture, which flourished in Lviv after the opening of the Technical School (later Polytechnic), the first higher-education technical academy on Polish lands. Polytechnic educated generations of architects who were influential in the entire country. Examples are: the main buildings of Lviv Polytechnic, University of Lviv, Lviv Opera, Lviv railway station, former building of Galicyjska Kasa Oszczędności, Potocki Palace. During the interwar period, Lviv was striving to become a modern metropolis, so architects experimented with modernism. It was the period of the most rapid growth of the city, so one can find many examples of architecture from this time in the city. Examples include the main building of Lviv Academy of Commerce, the second Sprecher's building or building of City Electrical Facilities. One monument of the Polish past is the Adam Mickiewicz Monument at the square bearing his name. Many Polish pieces of art and sculpture can be found in Lviv galleries, among them works by Jan Piotr Norblin, Marceleo Bacciarelli, Kazimierz Wojniakowski, Antoni Brodowski, Henryk Rodakowski, Artur Grottger, Jan Matejko, Aleksander Gierymski, Jan Stanisławski, Leon Wyczółkowski, Józef Chełmoński, Józef Mehoffer, Stanisław Wyspiański, Olga Boznańska, Władysław Słowiński, Jacek Malczewski. Poles who stayed in Lviv have formed the organisation the Association of Polish Culture of the Lviv Land.