During the highest tides the abbey is completely surrounded by water. During low tide the flat marshes provide food for the world's only herd of salt water plant eating sheep. Mont St. Michel's tides can rush in at incredible speeds. It's not uncommon to hear an announcement in French (and occasionally English!) over the islands PA system imploring a car owner to move his or her vehicle to an the auxiliary parking lot or risk seeing their car underwater within minutes. The sea can rise up to 45 ft. during high tide at Mont St. Michel