Also called the Stone Spheres of the Diquís or sim­ply “Las Balos” the Stone Spheres of Cos­ta Rica remain one of the biggest mys­ter­ies in archae­ol­o­gy. The more than 300 spheres, which are almost per­fect­ly round, were unearthed by work­ers clear­ing a field in the 1930s. They range in size and weigh up to 16 tons. They are amaz­ing man-made cre­ations, but no one real­ly knows how or why they were made by an ancient indige­nous cul­ture. Some of the stones are on dis­play at the Nation­al Muse­um of Cos­ta Rica while oth­ers are in their orig­i­nal spots at the Fin­ca 6 Muse­um and Archae­o­log­i­cal Site in Pal­mar Sur.