They've been called the world's greatest archaeological enigma. 2,000-year-old geoglyphs made in the Peruvian desert that span over 50 miles. The drawings are so massive, they can only be seen from the air. Can new research finally unravel their secrets? What is the true purpose of the incredible Nazca Lines?

In July 1996, one of the worst aviation disasters in American history leaves 230 people dead and countless questions unanswered; it's a tragedy that changes the aviation industry forever.