The 1794 Flowing Hair Silver Dollar currently maintains the distinction as the most expensive coin ever sold at auction.
The 1933 Double Eagle is surrounded by controversy and secrecy.
Existence is restricted to only three specimens, rendering it exceedingly rare.
Produced in 1787 by goldsmith Ephraim Brasher, the Brasher Doubloon is among the earliest examples of American gold coinage.
An additional treasure, the 1943-S Silver Washington Quarter is valued at more than $20,000.