In 1944 and 1945, at the end of World War II, both the Lower and the Upper Belvedere were badly damaged in air-raids.

1955 was a historic year for Austria. On May 15th, in the Marble Hall of Upper Belvedere the Austrian foreign minister Leopold Figl and representatives of the four signatories (the foreign ministers of the Allied Power - England, France, Soviet Union and United States of America) signed the Austrian State Treaty marking the end of the Allied occupation and restoring to Austria its freedom, independency and neutrality. With the words of Leopold Figl from the balcony of Upper Belvedere, "Austria is free", the second Republic of Austria was born.