As impressive as the Quadrifoglio versions of the Giulia and Stelvio may be, it's been a long time since Alfa Romeo has produced a proper supercar along the lines of a Ferrari or Bugatti. But before the Second World War, the 8C 2900 B was king. And a very rare example is coming up for auction next month, where it could easily sell for over $20 million.

Chassis number 412024 is one of fewer than 50 made and just five berlinettas coachbuilt by Carrozzeria Touring. Of the other four, two have won Best of Show at Pebble Beach.

And with good reason. Not only is it an achingly beautiful remnant of a bygone era, it was one of the fastest cars in its time. At the Mille Miglia in 1938, Scuderia Ferrari driver Carlo Pintacuda (long before the Prancing Horse marque made its own) averaged over 131 mph along the autostrada. This at a time when most cars could barely reach 60 mph, and very few could crack 90.

Owe that in no small part to the Tipo B grand prix racer with which the 8C 2900 B shared much of its underpinnings, a suspension designed by Porsche and a race-proven 2.9-liter supercharged V8.

Of the other four examples made, one remains part of the automaker's own in-house collection, and the other three have been extensively restored. This example, however, remains in highly original, unrestored condition. It's been owned by the same family for over 40 years, and is sure the attract a good deal of attention from the Pebble Beach set when it comes up for grabs it off during the Retromobile show in Paris on February 8. The auctioneers at Artcurial estimate its value at €16-22 million, or about $18-25 million at current exchange rates. (Beautiful photos by Kevin van Campenhout for Artcurial.)