the Karlstor (Karls gate).
This gate was part of a large 14th century city wall which replaced the smaller city wall from the 12th century. The city wall was destroyed at around 1800, and the Karlstor became the center of a new square, Karlsplatz. Two buildings were built next to the Karlstor, forming a symmetrical halve circle, symbolizing the opening of the city towards the outside.
