On the morning of April 20, 1914, Colorado National Guard troops opened fire on a tent colony of 1,200 striking coal miners at Ludlow, Colorado. They continued shooting until late afternoon, and then swept through the camp looting it and setting it aflame. When the smoke cleared twenty of the camps inhabitants were dead including two women, and twelve children. The Ludlow massacre is the most violent and the best-known event of the 1913-1914 Colorado Coal Field War, but its significance goes far beyond this struggle. The killing of women and children at Ludlow outraged the American public and helped to turn popular opinion against violent confrontations with strikers. It marks a pivotal point in U.S. history when labor relations began to move from class warfare to corporate and government policies of negotiation, co-option, and regulated strikes. Today, however, popular memory of the massacre has been largely lost outside of union circles, and the realities of class struggle in the United States buried.