Overview: Nearly half a century later, it remains history's deadliest air crash. The 1977 collision of two jumbo jets at a tiny airport in the Canary Islands horrified the world and sent investigators scrambling to understand what happened. Witness the runway disaster that claimed the lives of 583 passengers and crew. Then watch as examiners from Spain, the Netherlands, and the U.S. sift through the wreckage, the tower transcripts, and one pilot's flight log to untangle the chain of events that led to this catastrophic accident.