During the American Civil War, Chattanooga was a center of battle. Chattanooga served as a hub connecting fifty percent of the Confederacy's arsenals, those being located in Atlanta, Augusta, Columbus, and Macon. Chattanooga railroads proved vital in the Confederacy's transportation of raw material to processing plants where they were responsible for producing small arms munitions. During the Chickamauga Campaign, Union artillery bombarded Chattanooga as a diversion and occupied it on September 9, 1863. Following the Battle of Chickamauga, the defeated Union Army retreated to safety in Chattanooga. On November 23, 1863, the Battles for Chattanooga began when Union forces led by Major General Ulysses S. Grant reinforced troops at Chattanooga and advanced to Orchard Knob against Confederate troops besieging the city. The next day, the Battle of Lookout Mountain was fought, driving the Confederates off the mountain. On November 25, Grant's army routed the Confederates in the Battle of Missionary Ridge. In regard to victories won by the Union, Chattanooga marks one of three defining moments that turned the Civil War in their favor. The Battle of Gettysburg brought the streak of victories obtained by the Confederacy to an end, while the Siege of Vicksburg split the Confederacy itself in half, while Chattanooga served as the doorway to the deep south. These battles were followed the next spring by the Atlanta Campaign, beginning just over the nearby state line in Georgia and moving southeastward. After the war ended, the city became a major railroad hub and industrial and manufacturing center.