Central Morocco consists largely of the Atlas Mts., which rise to 13,671 ft (4,167 m) in Jebel Toubkal in the southwest and which dominate most of the country. In the south lie the sandy wastes of the Sahara desert. In the north is a fertile coastal plain. The population of Morocco is concentrated in the coastal region and the mountains, where rainfall is most plentiful. In parts of the Rif Mts. in the northeast some 40 in. (102 cm) of rain fall each year. There are no important rivers in the country, but dams on several coastal streams are used for irrigation and hydroelectric power. The vast majority of Moroccans are Muslims of Arab-Berber ancestry. There are also small Christian and Jewish minorities. Arabic and Amazigh (Berber) are official languages, but French (often used in business and government) also is spoken. More than half of all Moroccans live in urban areas.