The four-story Toll Tower was erected in the mid-15th century along with Fahrtor (gate). In front of it lay the harbour, where all trading goods came in or went out by river. In the “Toll Office”, the customs office on the first floor of the tower, the duties for imports and exports of goods had to be paid, and for over 500 years the tower was closed to the public. As part of modernizing the old museum buildings the clock was also restored – to give the Toll Tower back what was from the 19th century onwards its characteristic look with the two large black clock faces. The historical clockwork in the tower consists of a pendulum clockwork made in 1937.