By the time authorities intervened, dozens of stones were destroyed.
Over the next several decades around 300 stones were unearthed mostly in the Diquis Delta region.
However, its very difficult to estimate the age of the stones.
The spheres were dated by pottery styles and radiocarbon dates associated with archeological deposits found with the stone spheres.
Furthermore, most of these spheres are no longer in their original location.
Whoever created these spheres had craftsmen experienced enough to create polished surfaces.
And there is always the alien connection.
The stones are now protected under the United Nations, UNESCO, which declared them the heritage of humanity.
