Hofburg Palace
From Tardis Wiki, the free Doctor Who reference
Hofburg was the royal residence of the Austrian Emperor Franz Joseph and his wife Sisi in 19th century Vienna. The name was also used figuratively to refer to the royal family itself.
Hofburg was situated on the Ringstrasse and was one of the popular tourist attractions.
Sisi invited Alfred Stahlbaum to give a performance of the Silver Turk at the Hofburg on the 12 September 1873. However, his cab crashed with another at the turn for the Hofburg, and the performance did not happen. (AUDIO: The Silver Turk)