Human habitation of Stone Mountain and its surroundings date back into prehistory. When the mountain was first encountered by European explorers, its summit was encircled by a rock wall, similar to that still to be found on Georgia's Fort Mountain. The wall is believed to have been built by early Native American inhabitants of the area, although its purpose remains unclear. By the beginning of the 20th century, the wall had disappeared, the rocks having been taken away by early visitors as souvenirs, rolled down the rockface, or removed by the commercial quarrying operation. The mountain was the eastern end of the Campbellton Trail, a Native American path that ran through what is now the Atlanta area.