Netherlands and into Germany

This Holland Closure Dike is 30km long and 90m across and built 7m above sea level. It is almost a straight line except for the bend where it allows water from Usselmeer (lake) to be discharged into the Waddenzee and North Sea. It was in 1918 that they approved the plan to dam and partially reclaim the Zuiderzee in the Netherlands. Work began on the closure in 1927.