The story of the spheres’ discovery began in the early 1930s as the United Fruit Company was searching new grounds for banana plantations. A disease threatened the health of their crop on the Caribbean side of the isthmus. Searching the Pacific side, they found promising land within the Diquis Valley, not far from the coast where exports could be undertaken. They moved their headquarters from Limón to Golfito. When the United Fruit Company arrived, the town of Golfito was a simple fishing village on the eastern periphery of the Golfo Dulce. However, it was soon connected by rail line to the larger town of Palmar Sur, some eighty kilometers away.
The stone spheres came to light during early cultivation of the farmland. Most were discovered by workmen as they cleared and burned the jungle in preparation for planting. Recognizing the stones as man-made, the workmen pushed them aside with bulldozers and heavy equipment. At some point thereafter, they returned to the stone balls, and, inspired by stories of hidden gold, began to drill holes into them. Within the drilled holes they inserted sticks of dynamite, which they would use to remove stubborn roots and stumps. Unfortunately, several of the spheres were destroyed before authorities intervened. Some of the dynamited spheres have been reassembled and are currently on display at the National Museum in San José.
The first scientific investigation of the spheres was undertaken shortly after their discovery by Doris Stone, a daughter of a United Fruit Co. executive. These were published in 1943 in American Antiquity, attracting the attention of Dr. Samuel Lothrop of the Peabody Museum, Harvard University. In 1948, he and his wife attempted to excavate an unrelated archaological site in the northern region of Costa Rica. The government of the time had disbanded its professional army, and the resulting civil unrest threatened the security of Lothrop’s team. In San José he met Doris Stone, who directed the group toward the Diquís Delta region in the South-West and provided them with valuable dig sites and personal contacts. Lothrop’s findings were published in Archaeology of the Diquís Delta, Costa Rica 1963. Numerous myths surround the stones, such as they came from Atlantis, or that they were made as such by nature. Some local legends state that the native inhabitants had access to a potion able to soften the rock. Another calls for the center of the spheres to contain a single coffee bean. It is wrongly believed that the spheres are perfect. However they do have a surprisingly smooth surface. According to laser measurements by researchers from the University of Pennsylvania, the spheres were 96% perfect.
The stone spheres have been found in clusters of up to twenty, and often in geometric patterns such as triangles, rectangles or straight lines. Such alignments often point to the earth¹s magnetic north. A large number of the spheres have been located in the Diquis River Delta, with other popular sites being the southern cities of Palmar, Sur, Buenos Aires and Golfito as well as in the province of Guanacaste to the north and in the central valley. Archaeologists have been able to date the stones by the artefacts that have been found lying alongside them. Some of them have, thus, been dated as far back as 400 B.C.E.
The majority of them have, however, been dated between 800 and 1200 B.C.E. Many of these stones have been found near the remains of dwellings and in close proximity to grave sites. Some believed that the stones contained some hidden treasures and a few of them have been smashed to try to get at this supposed treasure. None has been forthcoming, however. Despite these losses, however, the National museum of Costa Rica has catalogued some one hundred and thirty existing stone spheres. However, many of them are not catalogued. This is because of the fact that many of the spheres have been removed from their original sites and used as ornaments in private homes, gardens and churches. Clearly, there are also many stones that still lie undiscovered.