April 20, 1914 dates the horrific incident of the deaths of innocent men, women, and children at Ludlow, Colorado. The coal strike against Rockefeller Colorado Fuel and Iron Company began when workers united together to demand recognition of the United Mine Workers of America (UMCA), wages increases, and an eight hour workday. When their demands were not met, miners and their families moved out of the houses provided by the Coal Company, and moved into tents. In response to the strike Rockefeller sent armed militia units to attack and raid the tents.