In July 1947, a mysterious object crashed near Roswell, New Mexico. The US military originally claimed it was a flying saucer but then changed their story. It became the biggest enigma in UFO history, and now 70 years later the family that started it all wants answers. History’s Greatest Mysteries: Roswell: First Witness follows the Marcel family - Jesse Marcel III, John Marcel, and Denise Marcel. They are the grandchildren of Major Jesse Marcel, the first person to see the wreckage in 1947. Major Marcel, an air force intelligence officer, was dispatched to the Roswell wreckage site and transported the wreckage back to a military base (stopping to show it first to his 12-year old son, Jesse Jr.). Both Marcels later said the craft was constructed from an unknown substance, like a liquid metal, with hieroglyphic-like markings on it. The family believes Major Marcel was forced by the U.S. government to deny he ever saw a UFO. They possess Major Marcel’s journal, believed to contain coded clues about the truth of what happened at Roswell and where alien wreckage might still lie buried. This diary will be decoded for the first time on TV...