The mystery behind the stone spheres of Costa Rica

Discovered in the 30's the stone spheres of Costa Rica, carved by the pre-Columbian people, remain a mystery for scientists up to this day. "Las Bolas", as they are called by the locals, were discovered in the Costa Rican jungle and most of them are no longer in their initial locations. According to researchers, the spheres were sculptured by human hands around the year 600, with the majority of the spheres dating after 1000 but before the Spanish conquest. Further information as to why the spheres were made are not available and more accurate dating of the stones becomes difficult, since they are no longer in their initial locations.  

Since their discovery, at Diquis Delta and the Isla de Caño, over 300 spherical stones have been documented in a variety of sizes, ranging from a few centimeters to over two meters in diameter. Some of the stones weight around 16tons and are made of hard, igneous stone called granodiorite. Unfinished stones were never found and all of them are monolithic. 

Different theories and legends have been developed regarding the purpose of the stones. Local legends state that the stones are the result of a potion able to soften the rock, possessed by the native population or that they came form Atlantis. John Hoopes, associate professor of anthropology at the Univ. of Kansas and director of the Global Indigenous Nations Studies Program, rejects many of the myths surrounding the stones, stating that "the main technique that was used was pecking and grinding and hammering with stones" finding spheres that "still have the marks of the blows on them from hammer stones".