Tensions boiled over in August 1921, after company agents assassinated a pro-union lawman named Sid Hatfield. At the time, the coal-rich region operated under the thumb of powerful mining interests who employed thuggish private detectives to harass any workers who tried to unionize. In 1921, the winding hills of southwest West Virginia played host to the largest and bloodiest labor dispute in American history. 1971 Miami Dolphins beat Kansas City Chiefs in NFL's longest game 3.