Great Zimbabwe

Complex ruins on Hill Complex, with the Great Enclosure wall on the right, Great Zimbabwe (UNESCO World Heritage List, 1986). Zimbabwe, 10th-15th century. DEA / S. VANNINI / De Agostini/Getty Images

Great Zimbabwe was a massive stone city in southeastern Africa that was a thriving trade center from the 11th to 15th centuries. But when Europeans first learned of it in the 16th century, they were certain it wasn't African at all.