About 500m southwest of the Old Town is the Rotunda – a ring-shaped fort 54m in diameter surrounding a circular yard. The rotunda was built in the 1820s as part of the defensive infrastructure of the town, but during WWII the German SS converted it into an interrogation centre. Some 8000 people from the Zamość area are believed to have been murdered here and their bodies burnt in the courtyard.
The graveyard surrounding the rotunda is the resting place of people who were killed here, including Polish soldiers and members of the Polish underground. Walking through the various cells (particularly by yourself) can be a disturbing and desolate experience.