The Hofburg, originally a medieval castle, was extended
to a magnificent residence when the Habsburg's power increased. Today,
you can find almost any architectural style there, from gothic to art
nouveau. This enormous complex is home to offices of the Austrian President,
Österreichische Nationalbibliothek (National Library), Schatzkammer
(Imperial Treasury), Museum für Völkerkunde (Museum of Ethnography)
and famous Spanische Hofreitschule (Spanish Riding School).