A huge, barn-like structure dating from 1391, the Bethlehem Chapel was where proto-Protestant Jan Hus delivered sermons in the Czech language, accusing the papacy of being, among other things, an institution of Satan. Given such remarks, it's perhaps unsurprising that, in 1415, he was burnt at the stake.
Before being thrown to the flames, Hus's last request was for 'history to be kind to the Bethlehem Chapel'. In response, the Jesuits bought the site and turned it into a woodshed. In the 18th century, German merchants moved in and built two houses within the walls. But Hus's wish was finally fulfilled under the communists, who chose to look on him as a working-class revolutionary thwarted by the forces of imperialism and spared no expense in the extensive restoration of the chapel. Three of the original walls remain and still show the remnants of the scriptures that were painted on them to enable people to follow the service. Following the fall of communism, religious services have resumed at the chapel, but secular visitors are also welcome.