On 14 December 1287, St. Lucia's flood affected the Netherlands and Germany, killing more than 50,000 people in one of the most destructive floods in recorded history. The St. Elizabeth flood of 1421 and the mismanagement in its aftermath destroyed a newly reclaimed polder, replacing it with the "Biesbosch" tidal floodplains in the south-centre. The huge North Sea flood of early February 1953 caused the collapse of several dikes in the south-west of the Netherlands; more than 1,800 people drowned in the flood. The Dutch government subsequently instituted a large-scale programme, the "Delta Works", to protect the country against future flooding, which was completed over a period of more than thirty years.