The Korean War originated in the division of Korea into South Korea and North Korea after World War II (1939-1945). In 1949, border fighting broke out between the North and the South. In China, the conflict was known as the War to Resist America and Aid Korea.

On June 25, 1950, North Korean forces crossed the dividing line and invaded the South. In defense of the South, the United States joined the fighting under the banner of the United Nations, along with British, Canadian, Australian and Turkish troops. The American forces advanced north towards the Chinese border at the Yalu River. This provoked the Chinese to launch a massive attack against the UN forces and South Korea. The Chinese armies forced the UN troops to retreat and Seoul fell in January 1951. The Chinese forces were halted only 60 miles from the 38th Parallel.

By the time a cease-fire agreement was signed on July 27, 1953, millions of soldiers and civilians had died. The fighting ended, but Korea has remained divided for decades since.