The House of the Cultures of the World used to be a Congress Hall. It was the US American contribution to the International Building Exhibition in 1957 and was declared as a gift of America to its close affiliate of West Berlin. The people of Berlin soon gave the building a fitting nickname: the "pregnant oyster". In 1980 part of the roof collapsed because the steel core of the front roof arch had rusted through. Although there was no concept for its use, the hall was reconstructed for the 750 year celebrations of Berlin in 1987. Since 1989 it has been used a site for events, exhibitions and festivals.