Approximately twenty-five years ago I heard rumors of some curious geological formations hidden high in the hills above the town of Ahualulco de Mercado, which is located about 58 kilometers west of Guadalajara, Mexico's second-largest city. "There are giant stone balls up there," I was told, "perfectly round and lying in a great bed of volcanic ash." When I asked how these megaspherulites (as scientists call them today) came into being, I was told that they had been shot into the air from inside Tequila Volcano. read more