The Markermeer is a lake that was for some time never supposed to be a lake. It used to be part of the Zuiderzee, a salt water inlet of the North Sea, that was dammed off by the Afsluitdijk (Closure-dike) in 1932, turning the Zuiderzee into the fresh water IJsselmeer. The following years would see the reclamation of extensive tracts of land through construction of large polders in a massive project known as the Zuiderzee Works (see there for map). One of these, the Markerwaard was to occupy the area of the current Markermeer. Part of the construction of this last polder was the building of the Houtribdijk, also called Markerwaarddijk, finished in 1976, which hydrologically splits the IJsselmeer in two, the southern section being the Markermeer.
Because of changing priorities and doubts about the financial feasibility the Markerwaard was indefinitely postponed in the 1980s and the Markermeer has since begun to become a valuable ecological and recreational asset of its own.