The Diquís Delta Mystery
Scattered across the Diquís Delta in southern Costa Rica are over 300 stone spheres, known locally as Las Bolas. These objects are remarkable for their near-perfect sphericity. They range in size from a few centimeters to over 2.6 meters in diameter, with the largest known example weighing approximately 24 tons. The vast majority are crafted from gabbro and granodiorite, hard igneous rocks sourced from the Talamanca mountain range, in some cases over 50 kilometers from where the spheres were found.
The spheres were created by the pre-Columbian Diquís culture, which flourished from approximately 700 AD to 1530 AD. This society left behind no written language, so the purpose and methods of the spheres' construction remain subjects of scientific investigation. The prevailing theory suggests a laborious process of shaping boulders through controlled fracturing, followed by pecking with harder stones and extensive polishing with sand. This technique, executed without metal tools or wheeled transport, allowed the Diquís to achieve a stunning degree of precision. The chiefdom settlements where the spheres are found were added to the UNESCO World Heritage Sites list in 2014.
Purpose and Rediscovery
The function of the spheres is not fully understood. Archaeologists have found them arranged in lines and geometric patterns, often associated with the approaches to the houses of chiefs or atop mounds. This placement suggests they were status symbols or held astronomical significance. One arrangement at the Finca 6 archaeological site appears to align with solar zenith events. They were not tools, but social or ceremonial objects.
The spheres came to wide attention in the 1930s when the United Fruit Company cleared jungle for banana plantations. Workers, unaware of their archaeological value, moved many with heavy machinery, causing damage and severing their connection to their original locations. Treasure-hunting myths, which incorrectly claimed the spheres contained gold, led to further destruction when people used dynamite to break them open. All have been found to be solid rock. The National Museum of Costa Rica has since worked to preserve and reconstruct damaged spheres. Today, Finca 6 is the only site where visitors can see some of the spheres in their original alignments.