Fort Breendonk is a fortification built in 1906 as part of the second ring of defenses of the Réduit national around the city of Antwerp, Belgium. Originally one in a chain of fortresses constructed to defend Belgium against a German attack, Breendonk was near the town of the same name, about 12 miles southwest of Antwerp. It was covered by a five metre thick layer of soil for defense against bombings, a water-filled moat and measured 656 by 984 feet. The fort was used as a prison camp by the German occupiers during World War II. Today, the site is a national memorial (Nationaal Gedenkteken Fort van Breendonk) and can be visited.