• Olduvai Gorge is a 30-mile rift in East Africa where many old layers of soil and rock are exposed.
  • Archaeologists have made major discoveries in the area since research began there in the early 1900s.
  • A stone ring uncovered at one dig site in the gorge is a possible remnant of shelter made by archaic humans.
  • The stones may have served to prop up the wooden sides of a hut—a building technique still used today by some African communities.
  • If the theory is correct, the remains are from the oldest known human-made structure in the world.