Berlin is a European centre for the arts and science as well as a gigantic museum for the history and the main ideologies of the 20th century. Visiting the Hansaviertel and the Frankfurter Allee is a hand-on lesson in architectural/ideological history. The Hansaviertel, constructed in 1957 by architects of the international avant-garde, was testimony to West Germany's re-arrival in the democratic world; the Karl-Marx-Allee was constructed at roughly the same time in the imperial Stalinist style, ideal for parades.