United Nations forces retake Seoul, crush the North Korean forces that tried to overrun the Pusan Perimeter and cross the 38th Parallel into North Korea, despite warnings from Communist China to intervene if the U.N. forces crossed into North Korea, and push toward Pyongyang, the capital of North Korea. U.S. Naval forces created what was to become the largest naval blockade in history off the strategically vital Wonsan harbor on North Korea’s east coast. U.N. forces, including the 1st Marine Division, capture Pyongyang October 19, 1950.