Instead, they found more than 300 stone spheres spread out randomly over the land without rhyme or reason. 
There are several theories behind these stones. Some people say that because they are shaped as spheres, they represent the moon and/or sun as something to be worshipped. 
How about aliens? Now there’s a more common subject for debate. 
My opinion on the spheres and their purpose? Honestly, I think it was originally a display.