Union troops capture Lookout Mountain southwest of Chattanooga, Tennessee, as they begin to break the Confederate siege of the city.

In the "battle above the clouds," the Yankees scaled the slopes of the mountain on the periphery of the Chattanooga lines. For nearly two months following the Battle of Chickamauga, the Confederates had trapped the Union army in Chattanooga.

The battle took place during the American Civil War and was part of the larger Chattanooga Campaign. Union forces under the command of General Joseph Hooker successfully assaulted the mountain, despite heavy fog and difficult terrain.

The victory at Lookout Mountain, combined with the subsequent Battle of Missionary Ridge, lifted the siege of Chattanooga and opened the door for Union forces to invade the Deep South.