Commemorative coins are among the most popular in American numismatics. Of these, the 1915-S $50 Panama Pacific Round is among the true classics.
The Panama is one of two $50 "slugs" - one version round, one version octagonal - of which only 1,500 examples each were ever produced, with limited distribution.
At the start of the 19th century, the round slugs were less popular to buyers than their octagonal counterparts.
But this soon changed, thanks to a disastrously unsuccessful annual convention held by the American Numismatics Association (ANA).
The primary draw for the convention was the Panama Pacific International Exposition, dedicated to the rare slugs.
At the time, the ANA was rocked by various issues - of members allegedly "buying" influence within the Association, and controversies surrounding the event's ethically dubious organiser, Farran Zerbe.
As a result, the convention was a flop, attended by fewer than two dozen people, the poorest turnout before or since.
After the event closed, Zerbe mounted an unsuccessful campaign to sell the slugs. After this failed, the 1,017 remaining unsold coins were returned to the Mint and melted down, leaving just 483 examples.
By the 1920s, the remaining $50 Panama coins had achieved premium value and were in strong demand, with their value appreciating by the year.
Today, the $50 pieces are the most sought after of the Panama Pacific Round coins - which saw the 1915-S $50 Panama Pacific Round leave the auction block priced at a staggering $54,990.