An aerial view as a high tide submerges a narrow causeway leading to Mont Saint-Michel, on France's northern coast, on March 21, 2015. #

People gather to watch waves breaking on March 21, 2015, in Wimereux, northern France. #

A group of people walk on the mud flats at low tide around the Mont Saint-Michel 11th-century abbey off France's Normandy coast on March 21, 2015. #

Surfers limber up as they wait to ride the wave of the tidal bore called Severn bore on the River Severn at Newnham in Gloucestershire, England, on March 21, 2015. #

Surfers catch the tidal bore wave on the River Severn at Minsterworth in Gloucestershire, England, on March 21, 2015. #

Surfers ride the wave of the tidal Severn bore on the River Severn at Newnham, England, on March 21, 2015. #

People dot the beach as they dig for shellfish during a record low tide in Saint Malo, western France, on March 21, 2015. #

People stand along the waterfront as a wave crashes onto a seawall during the rising tide in Saint Malo, on March 21, 2015. #

Mont Saint-Michel, off France's Normandy coast, on March 20, 2015, is nearly surrounded by the English Channel following exceptionally high spring tides. #

People make their way through waters during the outgoing tide at the Mont Saint-Michel 11th-century abbey on March 21, 2015. #

People sit on an embankment as the incoming high tide surrounds Mont Saint-Michel, off France's Normandy coast, on March 21, 2015. #