There is something very romantic about things emerging from under the waters: think the Lady of the Lake brandishing Excalibur, or a sunken town. Places such as the fabled Atlantis, Port Royal in Jamaica, Heracleon in Egypt, and storm-tossed Dunwich, generate stories of sunken church bells and ghostly apparitions. Some monuments escaped inundations: Abu Simnel was moved to avoid the rising waters of the Aswan dam while the architects of Rutland Water chose to protect Normanton church with a bund. As things stand, Venice will one day be faced with similar decisions if St Mark’s Square is not to slip below the Mediterranean waves.

The loss of Port Royal was instant and catastrophic; Dunwich took longer as the erosion of the coastline took centuries. For others it was the actions of man: the planned flooding of a river valley to create a reservoir.