The real highlight of the 14th-century Gothic Augustinerkirche (Augustinian Church) is not its pale, vaulted interior but a crypt containing silver urns with the hearts of 54 Habsburg rulers. The church hosts regular evening classical music concerts. The website (http://hochamt.augustiner.at) has details. Sometimes on a visit you can catch the choir practising. The crypt is open on Sunday after the 11am Mass (celebrated with a full choir and orchestra) – turn up around 12.30pm. Many Habsburg weddings took place here.