Precolumbian Chiefdom Settlements with Stone Spheres of the Diquís

The stone spheres of the Diquís remain one of the Americas' quiet enigmas: near-perfect granite balls from 0.7 to 2.57 metres across, made by a chiefdom society that thrived in southern Costa Rica between AD 500 and 1500, their purpose still unknown. Four archaeological sites in the delta preserve them beside mounds, paved areas and burials, saved from looting by centuries under protective sediment. UNESCO inscribed the settlements and spheres in 2014.