A gold medal from the 1908 Olympic Games in London is among items currently up for sale at the latest RR Auction.
The bidding has so far reached $20,000 (£16,000/€17,000) for the medal won by British wrestler Stanley Bacon in the freestyle middleweight category.
The medal, designed by Australian Bertram Mackennal and manufactured by Birmingham company Vaughton & Sons, is accompanied by its original red leather presentation case, with the top engraved in gilt with the event.
"Solid gold medals were awarded at only four Games – 1900, 1904, 1908, and 1912 – making this an especially appealing early Olympic piece," said Boston-based RR Auction.
"Great Britain's top finish in the Olympic medal table marks the only instance the country has done so in its history.
"Given that only 250 of these pure gold prizes were struck in 1908, this is a remarkable and exceptionally scarce winner's medal commemorating Great Britain's triumphant first outing as an Olympic host city."
Bacon's medal is one of seven Olympic golds up for grabs in the auction, which officially started last Friday (July 17) and is due to conclude tomorrow.
Another wrestling gold medal, this one from Los Angeles 1984, is also attracting strong interest with a bid of $11,000 (£8,500/€9.500).
It was won by Romania's Vasile Andrei in the Greco-Roman 100 kilograms.
Romania were the only Communist country to defy the Soviet Union's call to stay away from the Games in retaliation for the United States-led boycott of Moscow 1980 four years earlier.
Other gold medals up for grabs include the one won by the Soviet Union weightlifter Leonid Zhabotinsky at Tokyo 1964.
Zhabotinsky, who was born in Ukraine, set 19 world records in the super heavyweight class, and won a second Olympic gold medal at Mexico City 1968.
At the Opening Ceremony in Mexico City, Zhabotinsky stole the show by gripping the 40-pound Soviet Union flag with only one hand.
Among those who were inspired by Zhabotinsky was a teenage Arnold Schwarzenegger.
Bidding on the medal has so far reached $8,250 (£6,500/€7,000).
Other gold medals up for auction include another from the Soviet Union, won in the biathlon by Valeriy Medvedtsev in the 4x7.5 kilometres relay at Calgary 1988, which has so far attracted a bid of $10,000 (£8,000/€8,500).
A third gold medal won by a Soviet Union athlete is one of the three won during her career by fencer Tatyana Petrenko-Samusenko in the foil women's team at Munich 1972.
The other gold medals being auctioned were awarded to unnamed athletes in an unspecified event at Helsinki 1952 and in speed skating at Grenoble 1968.