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Like hitting the jackpot, but underwater, gold coins slowly revealed themselves through the sand in a few feet of water fifteen feet off shore.

William Bartlett was the lucky guy who came across the the treasure.

It was his third dive on a long day late last month. He may not have screamed, but there's no doubt he knew he uncovered something big.

Once ashore, Bartlett and the 1715 Fleet Queens Jewels Salvage Crew counted more than 300 gold coins valued at $4.5 million!

The larger coins, called Royals, tell an important story of the past.

Royals were specifically made for King Phillip V and are incredibly rare.

There were only 20 or so known to exist in the world before the crew found nine.

The king would present the coins to other important people in the monarchy.

The discovery of the nearly 300 coins was on the 300th anniversary of the wrecks, reminding Bartlett he's not just hunting for the flashy price tag, but pieces of history to preserve.

The salvage crew believes about $400 million worth of sunken treasure still lies undiscovered off the coast.

They are giving 20 percent of what they found to state museums.