In 1997, Sotheby's hosted a natural history auction selling wonders of our prehistoric world - but for the first time a dinosaur was on the books.
It was a niche event mostly attended by the world's museums looking for specimens to add to their collections.
The dinosaur in question was a Tyrannosaurus Rex called Sue - she was eventually sold for $8 million (£6 million) to the Field Museum in Chicago.
Nearly 30 years later, on Tuesday, another T. rex will make an appearance at the annual auction - one of the most complete specimens of this kind ever found, according to BBC.
And this time it is not just scientists who are dinosaur-hunting but also the super-rich.
The new specimen, known as Gus, has already been valued at $30 million but it could fetch more, possibly even becoming the most expensive dinosaur ever sold.
It adds to a growing debate in the natural history world – should specimens of such scientific importance be reserved for museums and their scientists?
Or - as auctioneers would argue - should fossil hunters be rewarded for their discovery of dinosaurs lost to science and saving them from a second extinction?
Cassandra Hatton, global head of natural history at Sotheby's, knows very well the lengths some fossil scientists - paleontologists - are willing to go to in the search for these creatures.
“People die on excavations,” she said.
And for many of these hunters, the ultimate prize is the Tyrannosaurus Rex.
This dinosaur that lived millions of years ago hardly needs describing, having been immortalized in culture by appearances in films like King Kong and Jurassic Park, and as the namesake of an English rock band.
“The people that look for these fossils will spend months out in the field with tents and their food in their backpacks and they're camping out in the middle of nowhere with the rattlesnakes and the bugs and the mountain lions,” she explained.
