Marsh castles

Bourtange (; Gronings: Boertang) is a village with a population of 430 in the municipality of Westerwolde in the Netherlands. It is situated in the region Westerwolde in the east of the province of Groningen near the German border. Fort Bourtange was built in 1593 during the Dutch Revolt and was used until 1851. Between 1967 and 1992 the star fort was gradually restored to its mid-18th-century state and it is currently an open-air museum.

lowland castle in boggy terrain