Chelm has Old Catholic and Orthodox churches. The most noteworthy is the Piast Church. The former Uniate church stands on Cathedral Mountain. It is surrounded by a complex of religious buildings that were once a bishops’ palace and a monastery. Chełm’s star attraction and a unique tourist route are its underground chalk tunnels that run under the city for two kilometers at a depth of 27 meters. The route leads through old chalk passages hewn out by hand. A ghost known as Bieluch sometimes appears as visitors pass through the galleries.