The closing of the Zuiderzee in order to create a vast inland lake and valuable polder lands is one of the greatest feats of human engineering in history. The Dutch already had a long history of land reclamation when they started this colossal work. After all, Holland, its most populous region, was in great part built on lands reclaimed on the North Sea since at least the 15th Century.
The Afsluitdijk, which links Holland and Frisia, is a 32km long causeway that was completed in 1933. This was the starting point of a project that saw the creation of four polders, two of which are known as Flevoland and form an entirely new province of the Netherlands. A second causeway was completed in 1975, isolating a new area called Markermeer from the larger IJselmeer. While Markermeer could easily be polderized, it is currently left under shallow waters for environmental reasons.
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The Zuydersee Works
