You're good to go!
Buy now, cancel later
In the oldest part of the Hofburg Imperial Palace you'll find perhaps the greatest treasury in the world. It holds gems, crowns, scepters, orbs, and regalia collected and hoarded by the Habsburg Empire over a period of more than 800 years. The items are visually stunning and historically significant. In fact, the actual Imperial Crown of the Holy Roman Empire rests here.
In addition to the worldly mementos of kings, queens, and emperors, there's also an ecclesiastical collection which features relics ascribed to various saints.