These large stones (up to 2.57m diameter) were carved into amazing perfect spheres and are estimated to be from 600 CE. They are located in the Diquís Delta in southern Costa Rica.

“On the small island of Isla del Caño and the Diquís Delta in Costa Rica are over 300 stone Petrospheres often referred to as the Diquís Spheres, that have been attributed to the now extinct Diquís culture.”

Source: https://www.heritagedaily.com/2021/06/the-mysterious-stone-spheres-of-costa-rica/139375

Source: https://whc.unesco.org/en/list/1453/