There was a time when this region of France was part of the territory of Flanders, where architecture and customs resembling those of Belgium and Holland. The English Channel is here at its narrowest part (the cliffs of Dover are seen in clear weather), by which Calais is one of the main ports of the passage to England, and now the Eurotunnel. The Opal Coast has beautiful beaches, the scene of terrible battles during World War II, such as Dunkirk.