The Valley of Stone Balls in Mangystau. As it turned out, there are many such valleys — somewhere there are more balls, somewhere fewer. We visited the best-known valley on the way to the Arykty Valley of Castles. No one could tell me how the stones become round, or whether they are already round underground, but what I saw with my own eyes gave rise to several guesses and hypotheses. Over years and millennia, the winds blow away the upper layer of earth and expose stone projections. When they reach the surface, these stone projections begin to erode — but in a very peculiar way: they flake off in a rounded shape and break away, forming a hemispherical surface. The projections that had been 1-2 meters beneath the surface eroded and formed complete spheres.