Hofburg Imperial Palace: The home of the great Hofburgs for 600 years, the palace now houses the Austrian president's offices, the Royal Treasury, Royal apartments and numerous celebrated museums. Look out for the Royal Chapel, too. The Vienna Boy's Choir sing Mass here every Sunday as they have since 1498. Other highlights include the Spanish Riding School's museum. A short walk away is the Spanische Hofreitschule where top equestrians on white Lipizzaner horses perform ‘ballet' to the sound of classical music.