The Dropa Stones were first discovered in 1938 in Bayan-Kara-Ula in Qinghai on the border of China and Tibet. Hundreds of 1-ft wide stone discs, the Dropa Stones, with 3/4-inch wide holes in their centres were found in the caves. On the walls the pictures of the rising sun, moon, stars, land, mountains, and lines of pea-sized dots connecting the earth with the sky were found. The discs and the cave drawings had been determined to be about 12,000 years old. Each stone disc had two fine grooves spiralling from the edge to the centre telling the story of the Dropa being a space probe.