A frantic search is currently underway in the North Atlantic for a missing submersible that was scheduled to take passengers on a unique visit to the Titanic wreckage. Concerns for the safety of the five people on board are increasing as time passes, given that the vessel only has a limited oxygen supply of 96 hours. Each passenger paid a hefty sum of $250,000 for the opportunity to explore the underwater remains of the illfated Titanic.