Transport in Western Sahara is very limited by sea, road and air with camels being the primary means of transportation in the desert area. Road transport by buses remain the major mode of transportation. The longest conveyor belt in the world is long, from the phosphate mines of Bu Craa to the coast south of Laayoune. The belt moves about 2,000 metric tons of rock containing phosphate every hour from the mines to El-Aaiun, where it is loaded and shipped. Portions of Western Sahara were a Spanish Colony till 1975 as the last colonial province in Africa. A war erupted between those countries and the Sahrawi national liberation movement, the Polisario Front, which proclaimed the Sahrawi Arab Democratic Republic (SADR) with a government in exile in Tindouf, Algeria. Mauritania withdrew in 1979, and Morocco eventually secured control of most of the territory, including all the major cities and natural resources. A UN brokered ceasefire was implemented from 1997 between Polisario and Moroccan forces. The world's longest cargo train, the Mauritania Railway cargo train, crosses the southeastern corner of Western Sahara for a short distance. Transit through Western Sahara was disrupted during the war between Polisaro and Moroccan forces before the ceasefire was implemented in 1997. Background Portions of Western Sahara were a Spanish Colony till 1975 as the last colonial province in Africa. A war erupted between those countries and the Sahrawi national liberation movement, the Polisario Front, which proclaimed the Sahrawi Arab Democratic Republic (SADR) with a government in exile in Tindouf, Algeria. Mauritania withdrew in 1979, and Morocco eventually secured control of most of the territory, including all the major cities and natural resources. Polisario was formed in 1973 to fight for the rights of Sahawari Arab African People. Polisario attacked Moroccan positions many times and have retaliated. Continued war was waged between Polisario and Morocco over prominence in the region backed by Algeria for Polisario and US, France and Saudi Arabia for Morocco. Polisario were successful in cutting the transport of Phosphorus across Western Sahara to the Atlantic Coast. The transport infrastructure of the region, including the border towns of Morocco was affected during the wars. Surface transport Western Sahara has no rail service, with the exception of a section of the Mauritania Railway; which (since the closure of the Choum Tunnel), cuts across the extreme south-eastern corner of the territory. The rail-route is considered the world's