In this week's Story of... video documentary maker Mark Apsolon tells the story of the Liberty head double eagle coin.
Apsolon traces the $20 coin's history from the Gold Act of March 3, 1849, introduced to meet demand for currency spurred on by the Gold Rush.
The $20 double eagle came into being following the correct assertion by James McKay, a North Carolina congressman, that it would prove more popular than its $1 equivalent.
What follows is a story that takes in corruption at the US Mint, the appointment of engraver James Longacre to design the coin, and how in 1849 - for just one day - the US had no President to govern over it...
Also fascinating is Longacre's appointment to design the coin. Experts and historians have since cast doubts over whether he was really qualified enough to do the job.
Yet, over a century later, the double eagle's continuing popularity among numismatists - and growing investment value - arguably puts paid to the doubters' arguments.
Only last week, a 1921 double eagle, graded MS63 by PCGS and pedigreed to the famous Norweb Collection, sold for an incredible $218,500 at Heritage Auction Galleries on April 29.
Elsewhere, at the Florida United Numismatics (or FUN) sale last January, a 1927-D Saint-Gaudens Double Eagle sold for almost $1.5m.
An internet bidder placed a winning bid of $1,495,000 for the coin - before the live auction had even started.
And, as if that isn't enough, the 1933 Double Eagle currently holds the record for highest value realised at auction by a single US coin, having once commanded a price of $7.59m.
While it only boasts the global coin market's second-highest value, the 1933 Double Eagle is in fact the rarest and most famous US coin in the world, with a current estimated market value of $8.9m.
The above video provides a fascinating and entertaining look at a coin that will continue to dominate the collectors' markets for many years to come.