The original cheque used to buy the Superman comic character from its original creators has been sold in an online auction for $160,000 (£101,000).
Jerome Siegel and Joe Shuster from Cleveland were paid $130 (£82) for all the rights to Superman by Detective Comics, later known as DC Comics.
The pair later tried to win back the rights to Superman in court, as it became part of a global industry.
The ComicConnect website has not revealed who won the auction.
"The concept of the superhero was born with Superman," Vincent Zurzolo, the co-founder of ComicConnect, told Reuters.
"That $130 cheque essentially created a billion-dollar industry," he added, with other characters such as Batman, Spider-Man and X-Men following in the footsteps of the Man of Steel.
ComicConnect told Reuters that when the first Superman movie came out in 1978, Mr Shuster was so poor he was working for a delivery company.
It was a box-office success followed by four more Superman films and a Supergirl version. Another is due for release in June 2013.
Although $130 is around $2,300 (£1,450) in today's money, it is a tiny fraction of what the character has earned since then.
The heirs of the creators Jerome Siegel and Joe Shuster are still involved in court battles with DC Comics as they try to reclaim their rights to the character.
The original cheque also paid the pair for earnings from other characters they were also working on for the company.
ComicConnect says the cheque was used in a court case in the 1970s, the last time Siegel and Shuster themselves tried to get the rights to Superman.
After their victory a DC Comics employee was told to throw away the court papers, but he held on to the cheque, recognising its significance.