The Netherlands Fortress Museum is located in the city of Naarden, in The Netherlands. The Museum was established in 1955 in the Turfpoort Bastion, one of the six bastions that give the walled city its distinctive star shape. (During World War II, allied bombers returning to Great Britain from bombing missions used it as a marker.) The fortifications themselves, including the bastions, date to the period 1675-1685.
The museum comprises several exhibits, including ones on fortification, garrison life, the Dutch Water Line, and the history of the city of Naarden. These are five metres underground in casemates; because they are underground, temperatures are relatively stable and the quarters are warm in winter and cool in summer. Above ground, the museum also contains a number of guns from the 19th Century.