Unraveling the Mysteries of Alleged Ancient Civilizations and Their Lost Technologies

7. The Giant Stone Spheres of Costa Rica
Discovered in the 1930s, these perfectly round stone spheres range in size and are thought to have been created around 600 AD. Their purpose and the technology used to shape them so precisely remain unknown. Some believe they were arranged by their creators for astronomical purposes, using a lost technology that could accurately shape solid stone.