A 1937 Bugatti type 57C sports tourer has sold for $9.7m in Bonhams' Amelia Island sale in Florida on March 10.
Only a handful of the model were ever built, most of which remain locked away in long-term collections.
It was the fastest production car of its era, easily capable of speeds up to 100mph.
The present lot is one of a rare few featuring coachwork built by outside contractors, in this case the legendary Belgian makers Vanden Plas.
Bonhams comments: "Authentic, well known and in impressive mechanical, structural and cosmetic condition, number 57541 embodies the very best of pre-war motoring.
"Its unbeatable combination of coachbuilt body and 1930s performance underpinnings result in a car of the highest known standards of the time.
"Athletic and tremendously aesthetic, this is the rarest of the rare and represents a once-in-a-lifetime opportunity."
Other top lots included a 1937 Mercedes-Benz 540K cabriolet that achieved a sale price of $2.9m.
The 540K was the last Mercedes-Benz built with a supercharger right up until the modern era. The present lot is one of only 32 examples to feature the sleek and attractive coachwork by Singelfingen.
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