The Hofburg Palace was the residence of the Habsburgs from the 13th century until 1918. Since 1945, it has been the seat of the Austrian Federal President. The palace is a complex of buildings, including 18 tracts and 19 yards on an area of 240,000 square meters and was built over 6 centuries - from 1279. Today, the Imperial Palace houses the National Library, the Museum of Musical Instruments, the weapons collection of the Emperor and the Spanish Riding School. Of great interest are the Imperial Treasury and the apartments of the Habsburgs, as well as the rooms of the famous and beautiful Empress Elizabeth /Sisi/.