The 1715 Spanish treasure fleet that wrecked off the Florida coast during a hurricane is probably the most famous of all US shipwreck treasures, with the possible exception of the Atocha hoard.
Pic of the new finds:
Those are what pirates called doubloons. By contrast, a piece of eight was a similar coin made of silver instead of gold.
I have a coin from the 1715 fleet myself, it is a silver 1-real coin:
I purchased it back in 1979 for $75, as I recall.