Bottmühle, Medieval tower in Altstadt-Süd, Germany.

The Bottmühle is a four-storey round stone tower windmill on a raised platform behind Cologne's medieval wall, between Bayenturm and Severinstorburg. It has a lower arched passage and round-arched windows, and is surrounded by a steep green slope where a 60-metre remnant of the city wall stands.

The Bottmühle is not part of Cologne's medieval wall: between 1550 and 1552 Alessandro Pasqualini built a gun platform, the "Bott", behind the wall. In 1587 the Kornherren commissioned Peter von Gleuel, trained in Holland, to build a wooden post mill for 500 guilders, finished in February 1588. From June 1677 to July 1678 stonemason Arnold von Gülich replaced it with a round stone tower mill on Pasqualini's old plans.

The name Bottmühle comes from the "Bott", the gun platform built by Alessandro Pasqualini between 1550 and 1552. From 1911 to 1945 the tower housed the student corporation ATV Markomannia-Westmark, and since 1970 it has been the seat of the Socialist Youth of Germany – Die Falken.

The tower is visible and reachable from the street within the Altstadt-Süd area. Best visiting times are during daylight hours when the surrounding district is active and you can observe the architecture clearly.

The Bottmühle is one of four mills built on or along Cologne's city wall. The street An der Bottmühle, 238 metres long, runs around it; at No. 2 stands the former Institute for Traffic Safety, built in 1923 by Wilhelm Riphahn and listed with the mill on 1 July 1980.