The Imperial Burial Vault, part of the Church of the Capuchin Friars on Neuer Markt in the old town, is the main burial site of the Habsburgs and deeply symbolic of the history of the dynasty. It is the final resting place of almost all of the Habsburg emperors since the start of the seventeenth century (except for Rudolf II, Ferdinand II and Karl I), containing the remains of some 150 members of the ruling family. The crypt goes back to a Habsburg foundation, and was extended several times over a period of several centuries. The sarcophaguses and tombs are decorated with religious motifs and symbols of the transience of worldly power. The Habsburg crypt is under the stewardship of the Catholic order of the Capuchin Friars, and is open to the public.
Source: Wien Tourismus