The decolonisation of Africa was a process that took place in the mid-to-late 1950s to 1975 during the Cold War, with radical government changes on the continent as colonial governments made the transition to independent states. The process was often marred with violence, political turmoil, widespread unrest, and organised revolts in both northern and sub-Saharan countries including the Algerian War in French Algeria, the Angolan War of Independence in Portuguese Angola, the Congo Crisis in the Belgian Congo, the Mau Mau Uprising in British Kenya, the Zanzibar Revolution in the Sultanate of Zanzibar, and the Nigerian Civil War in the secessionist state of Biafra. Background The "Scramble for Africa" between 1870 and 1914 was a significant period of European imperialism in Africa that ended with almost all of Africa, and its natural resources, being controlled as colonies by a small number of European states. Racing to secure as much land as possible while avoiding conflict amongst themselves, the partition of Africa was confirmed in the Berlin Agreement of 1885, with little regard to local differences. Almost all the pre-colonial states of Africa had lost their sovereignty, with the only exceptions being Liberia (which had been settled in the early 19th century by African-American former slaves) and Ethiopia (later occupied by Italy in 1936). Britain and France had the largest holdings, but Germany, Spain, Italy, Belgium, and Portugal also had colonies. The process of decolonisation began as direct consequence of World War II. By 1977, 50 African countries had gained Independence from European colonial powers. External causes During the world wars, African soldiers were conscripted into imperial militaries. Some African soldiers also volunteered. Veterans from over 1.3 million African troops participated in World War II and fought in both European and Asian theatres of war. This led to a deeper political awareness and the expectation of greater respect and self-determination, which was left largely unfulfilled. During the 1941 Atlantic Conference, the British and the US leaders met to discuss ideas for the post-war world. One of the provisions added by President Roosevelt was that all people had the right to self-determination, inspiring hope in British colonies. On February 12, 1941, United States President Franklin D. Roosevelt and British Prime Minister Winston Churchill met to discuss the post-war world. The result was the Atlantic Charter. It was not a treaty and was not submitted to the British Parliament or the Senate of