Now fully renovated, this tower/museum is an excellent introduction to the history of Tallinn's defences. Built 1475 - 1481, the 45m, six-storey cannon tower played a key role in the Livonian War and still has nine of Ivan IV's cannonballs embedded in its walls. The top floor houses a café with some excellent views. And where did the tower get its name? Check out the voyeur's view from the windows for yourself as you climb upward.

Admission €4.47. Joint ticket with the Bastion Tunnels €8.31.