Spain is situated south-western in Europe. Spain is One of Europe's largest countries; it is located on the Iberian Peninsula and also includes the Balearic and Canary islands. Spain's large central plateau is surrounded by the Ebro River valley, the mountainous Catalonia region, the Mediterranean coastal region of Valencia, the Guadalquivir River valley, and the mountainous region extending from the Pyrenees to the Atlantic coast. Spain is bordered on the west by Portugal; in the northeast it borders France, from which it is separated by the tiny principality of Andorra and by the great wall of the Pyrenees Mountains. Spain's only other land border is in the far south with Gibraltar, an enclave that belonged to Spain until 1713, when it was ceded to Great Britain in the Treaty of Utrecht at the end of the War of the Spainish Succession. Elsewhere the country is bounded by water: by the Mediterranean Sea to the east and southeast, by the Atlantic Ocean to the northwest and southwest, and by the Bay of Biscay (an inlet of the Atlantic Ocean) to the northwest. The Canary Islands, in the Atlantic Ocean off the northwestern African mainland, and the Balearic Islands, in the Mediterranean, also form parts of Spain, as do Ceuta and Melilla, two small enclaves in North Africa (northern Morocco) that Spain has ruled for centuries.