present day situation.
Zuiderzee has become:
[zee = sea / meer = lake]
because of the 'Afsluitdijk', the 30 miles long dike connecting the provinces
of Friesland and Noord-Holland, finished in 1932
here for more about the Afsluitdijk and former Zuiderzee
Mind that the former isles of Urk, Schokland and Wieringen are now incorporated into the Dutch mainland. [colored green on the map]