I recently spent a day on the Suffolk Coast. I haven't been for a number of years but I am there for longer next month.
Anyway one of the days I started at Dunwich.
Dunwich was a thriving town of 3000 people at the time of the Domesday book with 3 churches. In the thirteenth century a combination of storm surges and coastal erosion means washed most buildings away and today it is a small village. About 8 churches have disappeared.
It needs to be noted that storms alone didn't destroy the town. According to wikipedia ;) it developed as a sheltered harbour where the River Dunwich entered the North Sea. Coastal processes including storms caused the river to shift its mouth 2.5 miles (4 km) north to Walberswick, on the River Blyth. The town of Dunwich lost its raison d'etre and was largely abandoned. Sea defences were not maintained and coastal erosion progressively invaded the town.
Still there is a sizeable medieval town under the sea.
The ruins of the friary.