At present (ok, currently typing this but.. ) I'm reading some internet articles about Doggerland.. You know, the tundra like stretch of land between mainland N.W. Europe and the British Isles that went completely underneath seawater approx. around 8000 years ago. Final 'blow', that disconnected Brittany from Europe, was a tsunami caused by an underwater landslide near nowadays Norway presumably.
Kinda cool satellite 'picture' about Doggerland..
(it even had a land-bridge towards nowadays Sweden)