Claim: Świnoujście, a city on the Baltic Sea which was established in the twelfth century became part of Poland after the Soviet Union imposed new borders, which led to the entire population being expelled.
Evidence: Świnoujście [ɕfʲinɔˈui̯ɕt͡ɕɛ (listen) (German: Swinemünde [ˈsʋi:nəˌmʏndə, both names meaning Świna [river] mouth; Kashubian: Swina) is a city and seaport on the Baltic Sea and Szczecin Lagoon, located in the extreme north-west of Poland. After Germany's defeat in the war, the Soviet Union imposed new borders in eastern Europe at the Potsdam Conference, which made the area, including Świnoujście, a part of Poland. The entire population was expelled in accordance to the Potsdam Agreement and replaced by ethnic Poles. In the early 12th-century the island became part of the Duchy of Pomerania, founded as a vassal duchy of Poland.