The Molly Maguires were a group of 20 Irish coal miners suspected of murdering 16 people in the 1870s, in Pennsylvania. Coal miners in this region worked in harsh conditions with unsafe environments, inadequate wages, and extremely long hours. A group of angry miners organized a secret terrorist association to protest. The organization was accused of murdering their superiors and other members of the Reading Railroad. On June 21, 1877, known as “Black Thursday,” 10 of the accused men were hung for their involvement in the killings, and eventually the other 10 individuals were executed as well.