The round tower called „cobblestone” situated in the northern part of municipal wall, his origin dates the periode of Middle Ages. In XVIth century the tower was extended and adapted to the bigger number of canons becoming a strong fire position. Its vaults was used to the prison goals. During The Northern War (1703 r.) it was partly distroyed, rebuilt in the biginning of XX century and added a storey.

According to the Torun legend to honour the memory of the brave cat which became famous during the defence of Torun before Swedish in 1629, some part of the northern fortification was consacred to the brave cat memory. So there was in Toruń the Koci Łeb Tower, Kocie Łapy Towers (4 Towers), The cat's tail and the big barbican of Chelmno called Cat's abdomen. Of all presented only the first was preserved.