A mysterious Buddhist statue with a history that sounds like an Indiana Jones movie plot has extraterrestrial origins, researchers have discovered.
The 1,000-year-old artefact, stolen from Tibet by Nazi scientists in 1938, is carved from a meteorite.
Weighing 22lb, the statue known as the Iron Man is believed to portray Vaisravana, one of the Four Heavenly Kings in Buddhist mythology.
A large swastika in the centre of the 24 centimetre-tall figure may have enticed the German expedition leaders, who were supported by Nazi SS chief Heinrich Himmler. Swastikas decorate many Buddhist and Hindu statues. The ancient symbol was adopted by the Nazis, who modified it into a mirror-image form. Himmler believed the origins of the Aryan race could be found in Tibet.
The German expedition team, consisting of SS members, was headed by zoologist and ethnologist Ernst Schafer.
Precisely how the statue was found is unclear, but after being transported to Germany it became part of a private collection in Munich. Scientists were only able to study it after an auction in 2007.
Experts led by Dr Elmar Buchner, from the University of Stuttgart, analysed samples of the figure and found it was made of ataxite - a rare class of iron meteorite.
"The statue was chiselled from a fragment of the Chinga meteorite which crashed into the border areas between Mongolia and Siberia about 15,000 years ago," Dr Buchner said. "While the first debris was officially discovered in 1913 by gold prospectors, we believe that this individual meteorite fragment was collected many centuries before."
Details of the analysis are published in the journal Meteoritics and Planetary Science.
"The Iron Man statue is the only known illustration of a human figure to be carved into a meteorite, which means we have nothing to compare it to when assessing value," Dr Buchner said. "Its origins alone may value it at 20,000 dollars (£12,400). However, if our estimation of its age is correct and it is nearly 1,000 years old, it could be invaluable."