The Hofburg Vienna, historically also known as the Imperial Castle or Vienna Castle, was the residence of the Habsburgs in Vienna from 1279 to 1918 (with interruptions). Today, it is the seat of the Federal President, the Federal Monuments Office, the Austrian National Library, and several federal museums.
The complex, which grew over the course of approximately seven centuries, covers a usable area of approximately 24 hectares, making it the largest secular building complex in the world. The site also includes two religious buildings: the Hofburg Chapel and the Augustinian Church. Including the museums beyond the Ringstrasse – the Natural History Museum, the Art History Museum, and the MuseumsQuartier – the total area is approximately 50 hectares. The Hofburg received its current appearance from the Imperial Forum, begun by Gottfried Semper and Carl von Hasenauer but left unfinished after the death of Franz Joseph I.
Around 5,000 people live or work on the Hofburg grounds, which, together with Heldenplatz, are visited by around 20 million people annually. The Hofburg is owned by the Republic of Austria and administered by the Burghauptmannschaft (Austrian Burg Administration).