Frozen and bloodied, U.N. forces cursed the “Chinese Communist hordes” as they trudged back south from the Yalu River. They had thought they would be home by Christmas, but the fighting would continue for another two-and-a-half years.

This week marks 70 years since China's entry into the Korean War. Beijing’s intervention was decisive: Chinese “volunteers” saved Kim Il Sung’s North Korea from becoming a mere footnote in the history books.