An ultra-rare Ferrari [NYSE:RACE] headed to auction next month on the sidelines of the ritzy Monaco Historic Grand Prix could sell for upwards of $26 million.

The 1968 Ferrari 275 GTS/4 NART Spider was one of just 10 assembled, and it was the only one originally sold new in Europe. The other nine found buyers elsewhere. 

Ferrari's 275 range is generally regarded as its finest lineup of road-going vehicles. Even when new, the cars were snapped up by the world's most renowned enthusiasts. The model is probably best known for appearing on the silver screen with Steve McQueen at the wheel in The Thomas Crown Affair.

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1968 Ferrari 275 GTS/4 NART Spider

1968 Ferrari 275 GTS/4 NART Spider

However, this particular 275 is actually a little lighter in provenance. It was sold new to a Spanish Colonel of the Foreign Legion, but it later made its way through a series of British, Swiss, and American owners.  

Originally painted gray over black, it now wears more Ferrari-traditional dark red metallic paint with tan leather thanks to a 2001 restoration.

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One of its more recent claims to fame is that it was featured in both Octane and Thoroughbred and Classic Cars magazines. 

If the pre-auction high estimate of $26 million is a bit too rich for you, auctioneer RM Sotheby's will also have 20 more Ferraris up for grabs at the Monaco Historic Grand Prix on May 14. 

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