Sahrawi over 18 years of age that was part of the Spanish census or could prove their descent from someone who was. These 86,425 Sahrawis were dispersed between Moroccan-controlled Western Sahara and the refugee camps in Algeria, with smaller numbers in Mauritania and other places of exile. These numbers cover only Sahrawis 'indigenous' to Western Sahara during the Spanish colonial period, not the total number of "ethnic" Sahrawis (i.e., members of Sahrawi tribal groupings), who also extend into Mauritania, Morocco and Algeria. The number was highly politically significant due to the expected organization of a referendum on self-determination. The Polisario has its home base in the Tindouf refugee camps in Algeria, and declares the number of Sahrawi population in the camps to be approximately 155,000. Morocco disputes this number, saying it is exaggerated for political reasons and for attracting more foreign aid. The UN uses a number of 90,000 "most vulnerable" refugees as basis for its food aid program. Culture The major ethnic group of Western Sahara are the Sahrawis, a nomadic or Bedouin ethnic group speaking the Hassānīya dialect of Arabic, also spoken in much of Mauritania. They are of mixed Arab-Berber descent, but claim descent from the Beni Hassan, an Arab tribe that migrated across the desert in the 11th century. Physically indistinguishable from the Hassaniya-speaking Moors of Mauritania, the Sahrawi people differ from their neighbours partly because of different tribal affiliations (as tribal confederations cut across present modern boundaries) and partly as a consequence of their exposure to Spanish colonial domination. Surrounding territories were generally under French colonial rule. Like other Saharan Bedouin and Hassaniya groups, the Sahrawis are mostly Muslims of the Sunni branch and the Maliki fiqh. Local religious custom (Urf) is, like other Saharan groups, heavily influenced by pre-Islamic Berber and African practices, and differs substantially from urban practices. For example, Sahrawi Islam has traditionally functioned without mosques, in an adaptation to nomadic life. The original clan-/tribe-based society underwent a massive social upheaval in 1975 when the war forced part of the population to settle in the refugee camps of Tindouf, Algeria, where they remain. Families were broken up by the dispute. The Museum of the Sahrawi People's Liberation Army is located in this refugee camp. This museum is dedicated to the struggle for the independence of Western Saharan people. It presents weapons, vehicles and uniforms, as well as abundant documentation history. Cross-cultural influence