The Korean War was a result of the Cold War struggle between the United States and the Soviet Union. After World War II, Korea was divided along the 38th parallel, with the Soviet-backed Democratic People's Republic of Korea (North Korea) in the north and the US-backed Republic of Korea (South Korea) in the south. Tensions between the two sides escalated and eventually led to the outbreak of war on 25 June 1950, when North Korean forces invaded South Korea. The Korean War lasted for three years and resulted in a stalemate, with the border between North and South Korea essentially unchanged from where it had been prior to the war.