In years past, the Dutch coastline has changed considerably as a result of human intervention and natural disasters. Most notable in terms of land loss are the 1134 storm, which created the archipelago of Zeeland in the south west, and the 1287 storm, which killed 50,000 people and created the Zuiderzee (now dammed in and renamed the IJsselmeer — see below) in the northwest, giving Amsterdam direct access to the sea. The St. Elizabeth flood of 1421 and the mismanagement in its aftermath destroyed a newly reclaimed polder, replacing it with the 72 square kilometres (28 sq mi) Biesbosch tidal floodplains in the south-centre. The most recent parts of Zeeland were flooded during the North Sea Flood of 1953 when 1,836 people were killed, after which the Delta Plan was executed.