Coal miners in southwestern Colorado were mostly immigrants. They worked long hours under deplorable conditions for little pay, rented homes in company-owned camps, and purchased food from company-owned stores. In 1913, miners struck for higher pay and union recognition. The strikers moved out of their camps and built a tent colony near Ludlow. The Governor called out the militia, and on April 20, 1914, militiamen and company guards attacked the tent colony, killing 21, including 11 children. After the massacre, miners armed themselves, and in the labor war that followed, 30 more people died. President Woodrow Wilson sent in Federal troops. The strike was broken, and the miners voted to return to work with only minor improvements to their working conditions.