7. Bolas De Piedra (Stone Spheres)
These stone spheres were found in the intense tropical jungles of Costa Rica as workers were clearing away the dense foliage in the 1930s to make room for civilization.
These spheres were believed to have been created by a civilization called the Diquis, who lived in the area around AD 700.
Archaeologists have found over 300 such spheres ranging from ones the size of tennis balls to some that were over 8 feet in diameter.
It’s speculated that sculpting stones to this spherical shape was perhaps an art form practiced by the Diquis. However, how they achieved such spherical precision still remains a mystery.