The city has old Catholic and Orthodox churches. The most noteworthy is the Piarist Church from the 18th century. On the Cathedral Mountain stands the former Uniate church surrounded by a complex of religious buildings that were once a bishops' palace and a monastery. Chelm's star attraction is its underground chalk tunnels that run under the city for 2 kilometers at the depth of 27 meters and create a unique tourist route. The route leads through an array of the old chalk passages hewn out by hand.