In 1975, Morocco occupied much of the territory, now known as Western Sahara, but the Polisario Front, promoting the sovereignty of an independent Sahrawi Arab Democratic Republic (SADR), fought a guerrilla war for 16 years against Morocco. In 1991, the UN negotiated a ceasefire and has tried to arrange negotiations and a referendum to let the population vote on its future. Morocco controls the entire Atlantic coast and most of the landmass, population and natural resources of Western Sahara.