The area of Nowa Huta was a fertile countryside landscape in the Middle Ages. In the 6th century a mound was erected there by the Vistula People, one of the Polish tribes. In the 12th century the monks erected a monastery in Mogiła. After Poland was liberated and occupied by the Soviet Union the communists built the biggest European steel mill called Nowa Huta (New Steel Mill) from 1949 to 1955. The new district was built around Plac Centralny (Central Square) and Aleja Róż (Alley of Roses).Nowa Huta was a model city built to attract people from lower socioeconomic backgrounds to the region as a counterweight to the middle class of Kraków who had decisively rejected communism in the 1946 Polish People's Referendum. Nowa Huta became the largest steel mill in Poland but had little economic rationale: coal had to be imported from Silesia and iron ore from the Soviet Union, while most of the finished steel was shipped elsewhere as there was little local demand.It is one of the best examples of Socrealist architecture in Europe. Nowa Huta became the first atheist district in Poland, and it was not until the 1970s when the first church was built there and sanctified by then-Cardinal Karol Wojtyla, later Pope John Paul II.Andrzej Wajda's film Man of Marble shows the life of bricklayers building Nowa Huta in the 1950s and also the use of propaganda during the Stalinism period.