Berlin's history has left the city with a polycentric organization and a highly eclectic array of architecture and buildings. The city's appearance today has been predominantly shaped by the key role it played in Germany's history during the 20th century. All of the national governments based in Berlin the Kingdom of Prussia, the 2nd German Empire of 1871, the Weimar Republic, Nazi Germany, East Germany, as well as the reunified Germany initiated ambitious reconstruction programs, with each adding its own distinctive style to the city's architecture.