On Place de la Republique, in the City Hall (to the left of the main entrance) there is an unusual tourist site - Cryptoportiques. The entrance ticket costs 3.50 euros. Cryptoportics are underground arched galleries: three double tunnels. The northern and southern cryptoporticos are 90 meters long, the transverse western gallery connecting them is 60 m. Under the surface of the city they are lowered to a depth of 6 m. The original functions of cryptoporticos are still not entirely clear; at one time they were considered Christian catacombs.→