Location | Fort Bourtange, Groningen, Netherlands
Fort Bourtange is a star fort built in 1593 in order to control the only existing road between Germany and Groningen city. The the canals and lakes were used as moats, but did not have as great effect as assumed. After several battles the fort was used as a defensive are on the German border until 1851, when it was used as a village. Now the fort only serves as a museum for visitors.