Spain occupies about 85 percent of the Iberian Peninsula and is bounded by water for about 88 percent of its periphery; its Mediterranean coast is 1,660 km long, and its Atlantic coast is 710 km long. The long, unbroken mountain chain of the Pyrenes, extending 435 km from the Bay of Biscay to the Mediterranean Sea, forms the border with France on the north; in the extreme south the Strait of Gibraltar, less than 13 km wide at its narrowest extent, separates Spain from Africa. The most important topographical feature of Spain is the great, almost treeless, central plateau, called the Meseta Central, sloping generally downward from north to south and from east to west, and with an average elevation of 600 m above sea level. The tableland is divided into northern and southern sections by irregular mountain ranges, or sierras, of which the most important are the Sierra de Guadarrama, the Sierra de Gredos, and the Montes de Toledo. Between many of the mountains are narrow valleys, drained by rapid rivers. The coastal plain is narrow, rarely as much as 30 km wide and, in many areas, broken by mountains that descend to the sea to form rocky headlands, particularly along the Mediterranean coast, where the sole excellent harbor is Barcelona. The northwestern coastal area has several good harbors, particularly along the Galician coast. The six principal mountain chains have elevations greater than 3,300 m. The highest peaks are the Pico de Aneto 3,404 m in the Pyrenees and Mulhacn 3,477 m in the Sierra Nevada in southern Spain. The highest point in Spain and its insular territories is Pico de Teide 3,715 m on Tenerife Island in the Canary Islands. The lowest point is sea level along the coast. The principal rivers of Spain flow west and south to the Atlantic Ocean, generally along deep, rocky courses that they have cut through the mountain valleys. The Duero (Douro), Mio, Tajo (Tagus), and Guadiana rivers rise in Spain and flow through Portugal...
