At the end of World War II Berlin was split into 4 sectors by the Allies: the British, the French, the Americans, and the Russians. After the Berlin Wall was built, separating the Russian quarter from the rest of the city, Berlin spent almost thirty years split in two, developing as separate cities. With the demolition of the Wall in 1989, the East and West were reunited, but with two distinct urban identities. Modernization of the Eastern portion and the struggle to re-identify itself as a united entity has led to fertile ground for new architectural expression.