But colonialism also faced a lot of opposition, which proved to be its undoing. In India, for example, dislike of British rule united Hindu businesspeople and workers, and they formed the Indian National Congress, a political organization that began to push for independence. Confronted with increasingly strong resistance, the British tried a new system in which they gave some of their power to Indian ministers [source: Nowell, et al.].
But nationalist leader Mahatma Gandhi pushed even harder, braving prison to lead non-violent resistance against the colonial regime. In 1930, he even led followers on a march to the sea where they collected water in jars and evaporated it to obtain salt without paying tax, in defiance of colonial law [source: New York Times].
At the end of World War II, 750 million people — almost a third of the world's population — still lived in territory ruled by colonial powers [source: U.N.]. But after that, European nations, weakened both financially and politically by the war, saw their colonial empires rapidly disintegrate. Shortly after the war's conclusion, Indonesia declared its independence from Dutch rule. A violent conflict ensued but in 1949, the Dutch formally recognized Indonesia's independence.
In 1947, India achieved independence and split into two nations, Hindu-dominated India and predominately Muslim Pakistan [source: History.com]. After the costs associated with World War II and the loss of India, Britain grew less interested in and less able to maintain its global empire. The 1950s and 1960s saw many of its former colonies gain independence with little resistance from England [source: National Archives UK].
In 1954, the French were defeated militarily in Vietnam, and left after a treaty that split the country into communist and capitalist halves. Over the next decade, France, Belgium and Portugal lost hold of their remaining colonies in Africa.
In 1960, the United Nations General Assembly adopted a resolution that called for the end of colonialism "in all its manifestations." It proclaimed that people of every nation had the right to rule themselves, and instructed nations that still had colonies to take "immediate steps" toward transferring power to their subjects and granting them independence [source: U.N.].
But not every country wants independence.