The city was surrounded by defensive walls at the end of the 13th century. In the next century they were expanded.
Fortifications were erected from large granite pebbles, only their superstructure was finished with a burnt brick. They circled the town with a an irregular quadrangle, surrounded by an irrigated and in some places dry moat. There were towers at the corners. Two main gates led to the town: from the south Toruń Gate and Brodnia Gate from the north. The Castle Gate led to the Teutonic castle and in the north-east part, the Water Gate was placed. From the north-west there was a large area of the Teutonic castle, consisting of the upper castle and two parts of the outer wards.
To this day, a corner, cylindrical tower and a fragment of the wall at Fosa Jagiellońska street have survived.