On June 25, 1950, nearly 100,000 North Korean troops storm across the 38th parallel, overwhelming the border’s South Korean defenders. Two days later, U.S. President Harry Truman announced that the United States would intervene in the conflict, and on June 28, the United Nations approved the use of force against communist North Korea.
In the opening months of the war, the U.S.-led U.N. forces rapidly advanced against the North Koreans, but in October, Chinese communist troops entered the fray, throwing the Allies into a general retreat. In 1953, a peace agreement was signed, ending the war and reestablishing the 1945 division of Korea that still exists today. U.N. and South Korean forces suffered some 500,000 casualties in the Korean War, while communist losses were at least three times that.