Britain's relations with the other Great Powers were driven by the colonial antagonism of the Great Game with Russia, climaxing during the Crimean War; a "Pax Britannica" of international free trade was maintained by the country's naval and industrial supremacy. Britain embarked on global imperial expansion, particularly in Asia and Africa, which made the British Empire the largest empire in history. National self-confidence peaked. Britain granted political autonomy to the more advanced colonies of Australia, Canada, and New Zealand, and avoided war with the United States. Apart from the Crimean War, Britain was not involved in any armed conflict with another major power.