It is mankind's eternal question: are we alone in the universe? Adventurer and explorer Josh Gates sets off on a 50,000-mile, multi-continent quest to find the answer in Travel Channel's spellbinding four-week special event, Expedition Unknown: Hunt for Extraterrestrials. Gates' out-of-this-world mission takes him on an epic journey across North America, South America, Africa and Europe, searching for evidence of life beyond our planet and the truth behind longstanding extraterrestrial legends.