The Black Swan Project is the project name given by Odyssey Marine Exploration for its discovery and recovery of an estimated US$500 million (£314 million) worth of silver and gold coins from the ocean floor. Initially Odyssey kept the origin of the treasure confidential. It was later proved in trial that the recovered cargo was being carried by the Spanish frigate Nuestra Señora de las Mercedes, which sank off Portugal in 1804.
Knowledge of the recovery became public on May 18, 2007 when the company flew 17 tons of coins, mostly silver, from Gibraltar to a secure location of unknown address in Florida, USA. The company did not release the type, date, or nationality of the coins, while a rumor attributed it to the Merchant Royal, which sank near Land's End in 1641. At the time, Odyssey said that it planned to return to the site to perform an excavation expected to uncover more coins as well as other artifacts. However, Odyssey was sued by the Spanish government in U.S. courts, which eventually ordered the treasure to be returned to Spain. Odyssey pursued all legal avenues, even taking the case to the U.S. Supreme Court and losing. On February 27, 2012 the ship's treasure was flown back to Spain where the coins and other artifacts from the shipwreck are now exhibited in public museums. In 2015 a U.S. district court ordered Odyssey to pay Spain $1 million for "bad faith and abusive litigation."
Odyssey Marine stated on 21 May 2007 that most of the recovered coins and treasure are believed to be from a particular shipwreck, but it was likely that artifacts from other wrecks had also been mixed in and were recovered. Odyssey said that due to the location of the ship in an area known to contain a large number of colonial-era wrecks, the identity of the ship would not be disclosed pending further examination of the coins and artifacts. It was also thought the treasure might be from a ship that Odyssey had petitioned a federal court for permission to salvage, which was located off the southwest coast of the United Kingdom, within a five-mile (8 km) radius of 49°25′N 6°0′W / 49.417°N 6.000°W.