Treasure hunters have salvaged huge quantities of gold and silver coins from the ocean floor. For most people, sunken treasure ships exist only in adventure stories and tales of pirates, Spaniards and swashbuckling rogues. For the real life men and women who seek these treasures, however, the quest for the ocean's lost riches is a very real and potentially lucrative occupation.

On Sept. 4, 1622, the Nuestra Señora de Atocha set sail from Havana bound for Spain. The ship was laden with riches plundered from the conquered empires of the Americas. According to the Mel Fisher Maritime Museum, the Atocha's cargo included 24 tons of silver bullion, 18,000 pesos of silver coins, 582 copper ingots, 125 gold bars and 1,200 lbs. of silverware. The ship sank, taking its treasure and all but five of its crew to the ocean floor. Mel Fisher and his crew began the search for the treasure in 1969. On July 20, 1985, Mel Fisher's son Kane finally found the main pile of the ship's cargo.

In 1715, a fleet was bound for Spain carrying riches plundered from the New World. When the fleet was caught in a hurricane off the Florida coast, 10 of the 11 ships were sunk. The loss of the 1715 plate fleet was probably the largest loss of treasure at sea in all of maritime history. Kip Wagner, a beachcomber living on the Florida coast, discovered the location of the sunken treasure after finding a number of coins dated 1714 washed up on the shore.

During the 1850s, this steamship ran passengers and cargo between the eastern coast of the United States and Central America. In 1857, the steamer sank in a hurricane, taking her passengers and cargo to the ocean floor. The cargo included gold bars and coins worth an estimated $400 million. The Columbus-America Discovery Group, a salvage operation assembled to locate the wreck, found the SS Central America in September 1987, recovering vast quantities of gold worth.