Horizon follows a team of scientists set out to solve the mystery of chunks of ancient glass scattered in a remote part of the Sahara Desert. Their quest takes them on a perilous journey into the Great Sand Sea, the wastes of Siberia and the test site of the world's first atomic bomb in New Mexico. What their search uncovers is a devastating new natural phenomenon.

In 1996 in the Egyptian Museum in Cairo, Italian mineralogist Vincenzo de Michele spotted an unusual yellow-green gem in the middle of one of Tutankhamun's necklaces.

The jewel was tested and found to be glass, but intriguingly it is older than the earliest Egyptian civilisation.

Working with Egyptian geologist Aly Barakat, they traced its origins to unexplained chunks of glass found scattered in the sand in a remote region of the Sahara Desert.

But the glass is itself a scientific enigma. How did it get to be there and who or what made it?

The BBC Horizon programme has reported an extraordinary new theory linking Tutankhamun's gem with a meteor.

Film Duration: 48 min .