Perfect stone balls, hundreds of them, turned up in the 1930s when the United Fruit Company was clearing jungle for banana plantations in the Diquís delta. They run from a few centimetres to over two metres across, the largest measured at 2.66 metres, and the big ones weigh up to fifteen tons. Most are gabbro, some limestone or sandstone, and the working method looks brutally simple: hammer a natural boulder with other rocks, then polish it down with sand. The Diquís people made them, starting around 600 CE with most after 1000 and all of them before the Spanish arrived. Nobody knows what they were for. UNESCO listed the settlements in 2014 and Costa Rica made the spheres a national symbol the same year. Near Palmar Sur, Puntarenas.
Diquís Delta, Costa Rica
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