Karlovy Vary's most important Catholic church and one of its grandest baroque buildings, this imposing, twin-steepled structure in the heart of the spa dates from the 1730s and is the work of baroque master Kilian Dientzenhofer, the architect of St Nicholas Church in Prague's Malá Strana. The crypt contains an underground altar and an ossuary containing the bones from the 18th-century graveyard that once surrounded the church.