Twice a day, the sea goes up, and then goes down in the Mont St Michel Bay.  It is the tide. The Moon and the Sun attract all liquid on Earth.  It is the law of Mother Nature. As the Moon is much more close to Earth than the Sun, its action is the strongest, in spite of its small size.

Several assumptions are made about these mysterious menhirs. Certainly these menhirs have been placed on specific magnetic lines in the North/South axis, like needles of acupuncture on the skin of the Earth...