Korean War - Key Events
October 25, 1950
Having destroyed the bulk of the North Korean army, UN troops have pressed on into North Korea and are now approaching the Yalu River. Chinese People’s Volunteers Force (CPVF) troops under veteran commander Gen. Peng Dehuai cross into North Korea and inflict serious losses on the lead units of the UN advance. The sudden appearance of Chinese forces sends the main body of UN forces reeling back to the south bank of the Ch’ŏngch’ŏn River.
These events are taken from the Encyclopedia Britannica