United States salvage experts say they have found a shipwreck off the country's north-eastern coast, which may contain more than $US4 billion worth of treasure.
They think the wreck is that of a British freighter which was sunk by German submarines during the Second World War on its way to New York.
The exact location of the wreck is being kept secret to prevent any rival team reaching it first.
The salvagers have protected the ship's identity with the codename Blue Baron.
However, the leader of the expedition, Greg Brooks, told the BBC the vessel was a British freighter laden with around 70 tonnes of platinum, ten tonnes of gold and around 1.5 tonnes of industrial diamonds and gemstones.