The most important artifacts of the Holy Roman Empire

Undoubtedly the most important of Hofburg's museums, the Secular and Sacred Treasury contains wonders of the Holy Roman Empire, gold and precious stones aplenty, and a number of fascinating totemic artefacts. This museum houses some of the most beautiful gemstones in the world.

The entrance is beneath the steps to the Burgkapelle and best reached through the Schweizertor. Most of the exhibits were amassed by Ferdinand I (1521-64) but assembled in Hofburg under the reign of Karl VI in 1712. There are 20 smallish rooms with extremely subdued lighting and labelling in German; however, the entrance price includes the use of a device that gives an English commentary. In the secular section, top exhibits include the crown of Rudolph II (room 2) made in 1602 and festooned with diamonds, rubies, pearls and topped with a huge sapphire; the ornate silver cot of Napoleon's son, the Duc de Reichstadt (room 5); an amazing agate bowl once thought to be the Holy Grail, though more likely stolen from Constantinople in 1204; and opposite, the 'horn of the unicorn', a 2.4m- (8ft-) long narwhal's horn. In the twilight and confusing layout of the rooms, don't miss the star attraction: the Byzantine octagonal crown of the Holy Roman Empire. Finally, room 12 contains a number of relics – Karl VI was an inveterate collector of these – including splinters of wood that supposedly came from the True Cross, a shred of the tablecloth from the Last Supper and one of the teeth of John the Baptist.