Mysterious Symbols in Kazakhstan: How Old Are They, Really?

Sprawling earthen swastika designs, crosses and rings that cover part of Kazakhstan are becoming a little less mysterious: Archaeologists have found and investigated 60 of these symbols, called geoglyphs, and determined when they were created and what their potential function might have been. Using a dating technique called optically stimulated luminescence (OSL), the archaeologists recently found that the structures were constructed starting around 2,800 years ago.