Tide coming in in the bay of the Somme.
This is a large estuary in the North of France that covers a total area of 72 km2. The bay drains six rivers into the English Channel, principally the River Somme. When the tide is out, one can cross the wide, flat areas of marsh and sand to the other side. However, when the tide rises, the bay fills rapidly and a boat is needed for the crossing.
