Panorama of Marienplatz (Marian Place), Gruener Turm (Green Tower) and Frauentor (Women's Gate) in Ravensburg, Baden-Wuerttemberg, Germany. 

The Gruene Turm has its name from the green roof tiles. Built in the 15th century the tower formed once part of the fortification walls but was used as prison for most of its time. The Frauentor from 1318 was one of the gates to the city and is 35.5 metres high. Ravensburg has more than a dozen of towers from the 14th and 15th century and is often referred to as the city of towers.