Fort Breendonk is a former military installation at Breendonk, near Mechelen, in Belgium which served as a Nazi prison camp during the German occupation of Belgium during World War II.
Originally constructed between 1906 and 1913 as part of the second ring of the National Redoubt defending Antwerp, Fort Breendonk was used by the Belgian Army and was covered by a five-metre thick layer of soil for defense against artillery fire, a water-filled moat and measured 656 by 984 feet. It was used in both World War I and World War II by which time it had become militarily obsolete.
Fort Breendonk was requisitioned by the Schutzstaffel shortly after the Belgian surrender on 28 May 1940 and used as a prison camp for the detention of political prisoners, resistance members, and Jews.
Wikipedia https://en.wikipedia.org/wiki/Fort_Breendonk
Official Website https://www.fortbreendonk.be/
Coordinates 51°3'23.858" N 4°20'29.287" E