There are several joint projects with many other cities, such as Beirut, Belgrade, São Paulo, Copenhagen, Helsinki, Amsterdam, Johannesburg, Mumbai, Oslo, Hanoi, Shanghai, Seoul, Sofia, Sydney, New York City and Vienna. Berlin participates in international city associations such as the Union of the Capitals of the European Union, Eurocities, Network of European Cities of Culture, Metropolis, Summit Conference of the World's Major Cities, and Conference of the World's Capital Cities.