The Korean War
During 1950 the Korean Peninsula was split by a Soviet backed government in North Korea and an American backed government in South Korea. The invasion of north Korea had been by the Soviet Union and was currently being controlled by Japan since 1910. Korea had split up into two halves at the end of World War II.
MacArthur changed the course of the war overnight. This was because of his overnight, amphibious attack of port Inchon. The North Koreans were not prepared for such an attack and were defeated at the port. Then South Korean forces advanced farther into North Korea and then North Korea advanced into South Korea again. Finally, the two country met in the middle in a battle that would end the war.
War broke out on June 25, 1950 along the 38th parallel. The border that divided the two separate countries. The entry of the U.S. signaled a reversal of policy toward Korea. The U.S.'s decision was mainly made by the tension between Cold War politics. Many people died in the war as forces moved back and forth repetitively and there were many major battle such as port Inchon, and forces trying to approach the Yalu. The Yalu was what was building up. The Chinese were building up also and they stuck U.N. forces with great force and MacArthur was considering to ask Washington to fight off in China also. By Jan. 15th, when South Korea had fallen back, they started to slowly move forward again in what was called the meat grinder because many people died and reinforcements were constantly needed to make up for what was lost.
The 38th Parallel
The 38th parallel was the border that initially separated North Korea and South Korea before the Korean War. And it was where war first broke out in the Korean War.