Doggerland is a lost world which has disappeared beneath the North Sea as sea levels have risen. The last vestiges of this land was a series of islands which extended south-east from Spurn Point - these protected the Lincolnshire coast from tidal surges. Perhaps the most famous of these was the medieval pirate island of Ravenserodd, which thirteenth-century witnesses describe being thrown up by the waves in the mid-thirteenth century.
As the islands slowly eroded into the water, the Lincolnshire coast became susceptible to sea flooding. In August 1335 the waters broke through the sea-banks at Mablethorpe, drowning sheep and crops, while in 1425, the sea-banks were 'torn apart' and almost the whole town was submerged in both January and October. By 1500 old Skegness was thought to be 'in very great danger of the sea' and forty years later the old town had been lost, with just 'manifest tokens of old buildinges' visible at low tide, located around half a mile or so out to sea.