Expedition Unknown | The Return Of The Secret
01:39The secret is a continent-sized treasure hunt that's been going on for close to 40 years. In 1982 publisher Byron Preiss buries 12 treasure boxes in 12 North American cities and releases a book of enigmatic images and verses, offering clues to their locations: find a box and you recover a key, which can be redeemed for a valuable gemstone. To date, just 2 boxes have been found.