One of Vienna's most historic squares, this small plaza is now the site of an excavation revealing Roman plus 18th- and 19th-century layers of the past. The excavations are a latter-day distraction from the Michaelerplatz's most noted claim to fame—the eloquent entryway to the palace complex of the Hofburg.
Mozart's Requiem debuted in the Michaelerkirche on December 10, 1791. More people stop in today due to a discovery American soldiers made in 1945, when they forced open the crypt doors, which had been sealed for 150 years. Found lying undisturbed for centuries were the mummified remains of former wealthy parishioners of the church—even the finery and buckled shoes worn at their burial had been preserved by the perfect temperatures contained within the crypt.
Bilingual tours are offered from Easter to October, Monday–Saturday, at 11 and 1pm. The cost is €7. You're led down into the shadowy gloom and through a labyrinth of passageways, pausing at several tombs (many of which are open so you can view the remains) for a brief explanation of the cause of death. On Wednesday at 3 pm free tours of the church are held in English.