of roughly 1,000 in 1890, Amman grew to around 1,000,000 inhabitants in 1990, primarily as a result of immigration, but also due to the high birthrate in the city. Amman had been abandoned for centuries until hundreds of Circassians settled it in the 19th century. Today, about 40,000 Circassians live in Amman and its vicinity. After Amman became a major hub along the Hejaz Railway in 1914, many Muslim and Christian merchant families from al-Salt immigrated to the city. A large proportion of Amman's inhabitants have Palestinian roots (urban or rural origin), and the two main demographic groups in the city today are Arabs of Palestinian or Jordanian descent. Other ethnic groups comprise about 2% of the population. There are no official statistics about the proportion of people of Palestinian or Jordanian descent. New arrivals consisting of Jordanians from the north and south of the country and immigrants from Palestine had increased the city's population from 30,000 in 1930 to 60,000 in 1947. About 10,000 Palestinians, mostly from Safed, Haifa and Acre, migrated to the city for economic opportunities before the 1948 war. Many of the immigrants from al-Salt from that time were originally from Nablus. The 1948 war caused an exodus of urban Muslim and Christian Palestinian refugees, mostly from Jaffa, Ramla and Lydda, to Amman, whose population swelled to 110,000. With Jordan's capture of the West Bank during the war, many Palestinians from that area steadily migrated to Amman between 1950 and 1966, before another mass wave of Palestinian refugees from the West Bank moved to the city during the 1967 War. By 1970, the population had swelled to an estimated 550,000. A further 200,000 Palestinians arrived after their expulsion from Kuwait during the 1991 Gulf War. Several large Palestinian refugee camps exist around the center of Amman. Because Amman lacks a deep-rooted native population, the city does not have a distinct Arabic dialect, although recently such a dialect utilizing the various Jordanian and Palestinian dialects, has been forming. The children of immigrants in the city are also increasingly referring to themselves as "Ammani", unlike much of the first-generation inhabitants who identify more with their respective places of origin. Religion Amman has a mostly Sunni Muslim population, and the city contains numerous mosques. Among the main mosques is the large King Abdullah I Mosque, built between 1982 and 1989. It is capped by a blue mosaic dome beneath