Welthauptstadt Germania ('World Capital Germania') refers to the projected renewal of the German capital Berlin during the Nazi period, part of Adolf Hitler's vision for the future of Germany after the planned victory in World War II.

Albert Speer, the 'first architect of the Third Reich', produced many of the plans for the rebuilt city in his capacity as overseer of the project, only a small portion of which was realized between the years 1937 and 1943 when construction took place.