For over 200 years, $500 million in gold and silver cargo sat undisturbed on a seabed off the coast of Portugal. Then, in May of 2007, Florida-based Odyssey Marine Exploration announced the discovery of a vast treasure at an undisclosed location it called "the Black Swan." Within weeks, Spanish officials identified the Swan as the Spanish colonial-era galleon "Nuestra Señora de las Mercedes," declared her treasure to be the rightful property of the Spanish people, and demanded that Odyssey reveal its secret location. Now, two centuries after British cannon fire left the Mercedes "breaking like an egg, dumping her yolk into the deep," the Spanish warship has found herself at the center of another battle—exposing the fragile relationship between maritime law and cultural heritage protections.