The stone spheres of Costa Rica
The account
Nearly perfect spheres scattered through the jungle are said to be star maps, the work of Atlantis or of visitors.
What investigators found
They were carved by the Diquís peoples, who worked stone with other stones and abrasives. They became a UNESCO World Heritage Site in 2014.
The story
In the 1930s, workers clearing land for banana plantations in southern Costa Rica began finding enormous stone balls, some more than 2 meters across and weighing about 15 tons. More than 300 are known today.
The perfection of their curves fueled theories about ancient machines, Atlantis and aliens. Treasure hunters even blew some of them up, believing there was gold inside. Archaeologists know they were made by the Diquís peoples, between the years 300 and 1500, by pounding and polishing hard rock. What they were for, whether they marked power, territory or the sky, is still not known for certain.