Leiden had a number of strongholds with city gates and was completely surrounded by a defensive wall.
The Burcht fortress Leiden was a defensive structure. The 17th century gate is decorated with the arms of several mayors.
The typical round castle was built where two arms of the Oude Rijn meet. The Burcht also gave protection against the flooding of the Rhine.
De Gravensteen was also part of the fortress and is a picturesque complex from the 13th-16th centuries, which was used as a court of justice and prison.
Leiden criminals were hanged and exhibited at the gallows water, on the Oude Rijn.