Why the double eagle coin is worth up to $18.9million

When one version of the double eagle sold for $18.9 million at auction last year, it became the most valuable coin ever.

The last gold coin issued in the United States was the rare $20 coin.

Theodore Roosevelt sought to alter the appearance of American coins, particularly gold coins, in 1905.

The U.S. Mint claims that President Roosevelt thought the "coins of that era were unattractive" and wanted them to represent our sense of national identity and rising global preeminence.

As a result, the president decided to give American sculptor and artist Augustus Saint-Gaudens a dramatic makeover.

For the front of the coin, Saint-Gaudens chose Lady Liberty, a symbol of victory.

He continued by showing Lady Liberty holding an olive branch in her left hand and a torch in her right.

In response to Roosevelt's declaration, 445,500 1933-dated double eagle coins made at the Philadelphia Mint were melted down to create gold bars.

The Smithsonian Institution received only two of the preserved coins.

20 double eagles were also taken from the Philadelphia Mint and found in the possession of various people before the coins were melted.

The only 1933 double eagle coin that is legitimately privately owned is the one that will be auctioned off at Sotheby's in the summer of 2021.