The Korean War was a conflict that took place from 1950 to 1953 on the Korean Peninsula. It began when North Korea, supported by the Soviet Union and China, invaded South Korea. The war saw the involvement of United Nations forces, primarily from the United States, who came to aid South Korea. The fighting ended in a stalemate, leading to an armistice agreement in 1953, but no formal peace treaty was signed. As a result, North Korea and South Korea remain technically at war, divided by the Korean Demilitarized Zone (DMZ).