A single Spanish galleon sank in 1622 carrying cargo worth up to half a billion dollars in today's money, crippling an empire. Even after a 350-year hunt, fatal accidents, a Supreme Court battle, and a Guinness World Record, its most valuable part is still missing.

This episode follows the Nuestra Senora de Atocha from the desperate financial crisis that forced it into hurricane season, through the brutal salvage that exploited enslaved divers, to Mel Fisher's obsessive 16-year modern search. It's a dark saga of ambition, exploitation, and the human willingness to risk everything for treasure.

• How Spain's Thirty Years' War debts forced the treasure fleet to sail at the statistical peak of hurricane season
• The catastrophe that killed all but five of the Atocha's 265 people, who clung to the mizzenmast above the water
 ...