A submarine carrying tourists to see the wreckage of the Titanic is missing. The Boston Coast Guard is currently conducting a search and rescue mission about 400 miles off the coast of Newfoundland, Canada. British billionaire Hamish Harding is reportedly a passenger on the ship. The submersible is owned by OceanGate Expeditions which is a private company that recently began expeditions to view the historic Titanic wreckage.