Legend has it that in the early days, a vast forest extended around Mont-Tombe (the first name of Mont-Saint-Michel). A divine storm is said to have swept away the trees and the sea, turning the mountain into a bitter rock surrounded by sand. In the bay of Mont-Saint-Michel, the tide rises very quickly, at the speed of a galloping horse goes the saying. Probably a bit of an exaggeration, but its speed is still about 8-10 km/h. When the Moon and the Sun are aligned with the Earth, their forces of attraction accumulate and generate the great tides.