segregation. Large numbers of white immigrants who moved to the Congo after the end of World War II came from across the social spectrum, but were nonetheless always treated as superior to black people. During the 1940s and 1950s, the Congo experienced an unprecedented level of urbanisation and the colonial administration began various development programmes aimed at making the territory into a "model colony". One of the results of the measures was the development of a new middle class of Europeanised African "évolués" in the cities. By the 1950s the Congo had a wage labour force twice as large as that in any other African colony. The Congo's rich natural resources, including uranium—much of the uranium used by the U.S. nuclear programme during World War II was Congolese—led to substantial interest in the region from both the Soviet Union and the United States as the Cold War developed. Politics and radicalisation An African nationalist movement developed in the Belgian Congo during the 1950s, primarily among the évolués. The movement was divided into a number of parties and groups which were broadly divided on ethnic and geographical lines and opposed to one another. The largest, the Mouvement National Congolais (MNC), was a united front organisation dedicated to achieving independence "within a reasonable" time. It was created around a charter which was signed by, among others, Patrice Lumumba, Cyrille Adoula and Joseph Iléo, but others accused the party of being too moderate. Lumumba became a leading figure within the MNC, and by the end of 1959, the party claimed to have 58,000 members. The MNC's main rival was the Alliance des Bakongo (ABAKO), led by Joseph Kasa-Vubu, who advocated a more radical ideology than the MNC, based around calls for immediate independence and the promotion of regional identity. ABAKO's stance was more ethnic nationalist than the MNC's; it argued that an independent Congo should be run by the Bakongo as inheritors of the pre-colonial Kingdom of the Kongo. The Confédération des Associations Tribales du Katanga (CONAKAT), a localist party led by Moïse Tshombe, was the third major organisation; it advocated federalism and primarily represented the southern province of Katanga. These were joined by a number of smaller parties which emerged as the nationalist movement developed, including the radical Parti Solidaire Africain (PSA), and factions representing the interests of minor ethnic groups like the Alliance des Bayanzi (ABAZI). Although it was the largest