The Damsluis in Haarlemmermeermeerringvaart bij Halfweg is a part of the defence line which was built at the end of the 19th century. The line took 40 years to complete, and was a replacement for an older fortification which was made ineffective with the increased use of long range artillery. The line consists of a series of locks, dikes, and canals, and worked by flooding areas of land during times of invasion, making it difficult for the enemy to travel across the land.
