The Austro-Hungarian Empire was no less decadent than other royal houses in Europe and the Kaiserliche Schatzkammer (Imperial Treasury) holds what is considered the greatest treasury collection in the world. In the Secular Treasury, the baubles and finery span a millennium of European history, including the massive imperial crown, which dates from 962. It's so large that, though padded, it probably slipped down the forehead of many a Habsburg at his coronation. Embellished with emeralds, sapphires, diamonds, and rubies, this priceless treasure is the museum's most prized possession. The collection also includes one of the world's largest sapphires as well as a narwhal tusk, long mistaken for a unicorn's horn, and an ancient agate bowl, thought to be the holy grail. The Ecclesiastical Treasury has more questionable treasures, like alleged fragments of Jesus's cross, a nail from the crucifixion, or a table cloth from the Last Supper. A visit to the Schatzkammer can take from 30 minutes to two hours.