The remains of the former town walls and the Ostrowska Gate. The fortification is from the turn of the 14th century and consisted of three gates: Ostrowska, Klasztorna and Krośnieńska. The construction started in 1311. At the gates there used to be castellums with viewing towers and defensive bastilles. Since the demolition of the gates in the 19th century the cylindrical tower of the Ostrowska Gate has remained.