Calais is a city and major ferry port in northern France in the department of Pas-de-Calais, of which it is a sub-prefecture. Although Calais is by far the largest city in Pas-de-Calais, the department's prefecture is its third-largest city of Arras. The population of the metropolitan area at the 2010 census was 126,395. Calais overlooks the Strait of Dover, the narrowest point in the English Channel, which is only 34 km wide here, and is the closest French town to England. The White Cliffs of Dover can easily be seen on a clear day from Calais. Calais is a major port for ferries between France and England, and since 1994, the Channel Tunnel has linked nearby Coquelles to Folkestone by rail.
Due to its position, Calais since the Middle Ages has been a major port and a very important centre for transport and trading with England. It was annexed by Edward III of England in 1347 and grew into a thriving centre for wool production. The town came to be called the "brightest jewel in the English crown" owing to its great importance as the gateway for the tin, lead, lace and wool trades. Calais was a territorial possession of England until its capture by France in 1558.