The New Dutch Water line is a piece of land that served as defense against invasions when the land was covered with water. No surprise then that the technique of putting the land under water as a defense against invaders worked successfully numerous times in the past.
Like in 1672 when an invasion by the French was prevented. Because the high level of water they were forced to retreat.
When making a trip there nowadays and realizing that this line ran from Muiden in North-Holland down to Werkendam in Brabant. In Muiden you can also visit the Muiderslot and the Westbatterij, one of the fortresses.
The address on the map below is of the Fortress Rijnauwen, with 31 acres the largest fortress of the New Dutch Water Line.
Video New Dutch Water Line