Doggerland

Doggerland was an area of land, now lying beneath the southern North Sea, that connected Great Britain to mainland Europe during and after the last Ice Age. It was then gradually flooded by rising sea levels around 6,500–6,200 BCE. Geological surveys have suggested that it stretched from Britain's east coast to the Netherlands and the western coasts of Germany and the peninsula of Jutland. It was probably a rich habitat with human habitation in the Mesolithic period, although rising sea levels gradually reduced it to low-lying islands before its final destruction, perhaps following a tsunami caused by the Storegga Slide.