Fort Island IJmuiden (Dutch: Forteiland IJmuiden) is situated at the estuary of the Noordzeekanaal and is part of the Defence Line of Amsterdam.
This sea fort island was built in 1885 as the most important advanced defence post of the entrance to Amsterdam.
The beautiful, half underground fort is the biggest of the Defence Line and an UNESCO-World Memorial.
During the Second World War, the Fort island was part of the Atlantikwall, which explains the presence of the later built bunkers.