The Korean War began in 1950 when North Korean troops invaded South Korea, crossing the 38th parallel dividing line. The United Nations backed the US-led defense of South Korea in an effort to contain communism. Fighting escalated as Chinese troops joined the North Koreans, pushing UN forces back below the 38th parallel. The war settled into a stalemate along the border until an armistice was signed in 1953, leaving Korea still divided at the 38th parallel. The war had significant effects including the rise of the US military-industrial complex and the desegregation of American military units.