5. North Korea vs. United States & Allies
In June 1950, North Korea, supported by the Soviet Union and China, invaded South Korea, initiating the Korean War. The United Nations, led by the United States, intervened on behalf of South Korea. Despite initial successes by North Korean forces, the entry of Chinese troops in late 1950 led to a protracted and bloody conflict. The war concluded in July 1953 with an armistice agreement, leaving the Korean Peninsula divided along the 38th parallel, a division that persists today. (britannica.com)
