Scientists have uncovered evidence from around the world that indicates the early Dark Ages may have been triggered by an actual event that occurred around 535 A.D.

For nearly a century, humans forgot their glorious past and huddled in a state of ignorance and fear. Scientists have uncovered evidence from around the world that indicates the early Dark Ages may have been triggered by an actual event that occurred around 535 A.D. Science writer David Keys believes that the cause was a natural phenomenon of cataclysmic proportions. Determined to discover the exact nature of this catastrophe, and to understand its political, economic and social repercussions, he embarks on a scientific odyssey that ranges from Greenland to the Antarctic, from the Americas to the Far East. At the center of a stunningly complex chain of events seems to be a loud bang volcanic explosion (according to Keys, equal to two thousand million Hiroshima-size bombs). The subsequent environmental calamity, he believes, affected human civilization from Mongolia to Constantinople, precipitating plague, famine, death, great migration, the fall of the great Mexican city of Teotihuacan, the Anglo-Saxon victory over the Celts. The event may even have played a role in the rise of Islam. Roy Scheider narrates.