It’s only taken 4,500 years, but the quarry from which the stones for Stonehenge were taken in 2,500 BC has been found. “Archaeologists have long suspected that the bluestones, which form Stonehenge’s inner circle, came from the Preseli Hills, but no evidence of a quarry had been found in the area. Darvill and Wainwright report that geochemical analysis show that the rock formations at the prehistoric quarry are identical to those at Stonehenge.”