Kaiserliche Schatzkammer (Imperial Treasury)

The Imperial Treasury holds what is arguably the single most important collection of medieval and early modern royal regalia in the world, assembled over centuries in the secure vaults beside the Hofburg's Imperial Chapel. Its centrepiece is the Imperial Crown of the Holy Roman Empire, an octagonal 10th-century masterpiece of gold, enamel and gemstones that crowned Holy Roman Emperors for over 500 years, displayed alongside the Holy Lance, an artefact long associated (on flimsy but persistent tradition) with the spear that pierced Christ at the Crucifixion.

Beyond the imperial regalia, the Treasury holds the ceremonial vestments and jewels of the Order of the Golden Fleece, one of the world's largest cut emeralds, and two objects the Habsburgs once considered so extraordinary they were declared inalienable heirlooms: a giant narwhal tusk long believed to be a unicorn's horn, and a Late Antique agate bowl once thought to be the Holy Grail.