overtaking the economy of West Germany to become the second-largest in the world. The United States withdrew its military forces from the Vietnam War. In 1979, the Soviet Union invaded Afghanistan, which led to the Soviet–Afghan War. The 1970s saw an initial increase in violence in the Middle East as Egypt and Syria declared war on Israel, but in the late 1970s, the situation in the Middle East was fundamentally altered when Egypt signed the Egyptian–Israeli Peace Treaty. Political tensions in Iran exploded with the Iranian Revolution in 1979, which overthrew the Pahlavi dynasty and established an Islamic republic under the leadership of Ayatollah Khomeini. Africa saw further decolonization in the decade, with Angola and Mozambique gaining their independence in 1975 from the Portuguese Empire after the Carnation Revolution in Portugal. The continent was, however, plagued by endemic military coups, with the long-reigning Emperor of Ethiopia Haile Selassie being removed, civil wars and famine. The economies of much of the developing world continued to make steady progress in the early 1970s because of the Green Revolution. However, their economic growth was slowed by the oil crisis, although it boomed afterwards. The 1970s saw the world population increase from 3.7 to 4.4 billion, with approximately 1.23 billion births and 475 million deaths occurring during the decade. Politics and wars Wars The most notable wars and/or other conflicts of the decade include: The Cold War (1945–1991) The Vietnam War came to a close in 1975 with the fall of Saigon and the unconditional surrender of South Vietnam on April 30, 1975. The following year, Vietnam was officially declared reunited. Soviet–Afghan War (1979–1989) – Although taking place almost entirely throughout the 1980s, the war officially started on December 27, 1979. Angolan Civil War (1975–2002) – resulting in intervention by multiple countries on the Marxist and anti-Marxist sides, with Cuba and Mozambique supporting the Marxist faction while South Africa and Zaire support the anti-Marxists. Cambodian Civil War (1967–1975) ends with the Khmer Rouge establishing Democratic Kampuchea. Ethiopian Civil War (1974–1991) The Portuguese Colonial War (1961–1974) The Bangladesh Liberation War of 1971 in South Asia, engaging East Pakistan, West Pakistan, and India 1971 Bangladesh genocide Indo-Pakistani War of 1971 Arab–Israeli conflict (Early 20th century–present) Yom Kippur War (1973) – the war was launched by Egypt and Syria against Israel in October 1973 to recover territories lost by the Arabs in the 1967 conflict. The Israelis