from wikipedia: "Today F.A. Mitchell-Hedges is best known for his connection to a famous crystal skull which was in the possession of his adopted daughter (Anna) until her death in April 2007. He claimed to have discovered what he termed "The Skull of Doom" at the Maya ruin of Lubaantun (which he also claimed to have discovered) in British Honduras in the 1920s. However Mitchell-Hedges published no mention of the skull until the late 1940s, not long after a crystal skull was auctioned off at Sotheby's in 1943. Some think that Mitchell-Hedges crystal skull is actually the one from Sotheby's.
"Thirteen crystal skulls of apparently ancient origin have been found in parts of Mexico, Central America and South America, comprising one of the most fascinating subjects of 20th Century archaeology."
"The skulls’ legend has spawned a new breed of followers. New-agers have associated the skulls with the belief that the Mayan “long count” calendar runs out on Dec 21, 2012, when it reaches the end of a 5,126-year cycle. According to this theory, all 13 skulls must be reunited and lined up together to prevent the world from falling off its axis."
I better stock up on dramamine.