For more than six centuries the seat of the Habsburgs – and the official residence of every Austrian ruler since 1275 – the Hofburg is perhaps the most historically significant of Vienna’s palaces. The official seat of the Austrian President, this sprawling complex consists of numerous buildings reflecting various periods, including architectural flourishes from the Gothic, Renaissance, Baroque, and Rococo movements. The complex covers 59 acres with 18 groups of buildings, including 19 courtyards and 2,600 rooms. Its main attractions are the Imperial Apartments, the Sisi Museum, and the Silver Collection, while other notable sites within the complex include the Imperial Chapel (Burgkapelle) and the Hofburg Treasury with its large collection of Imperial regalia and relics of the Holy Roman Empire.