We've seen plenty of rare and valuable Aston Martins go under the hammer, but none are as historically significant as this vintage DBR1 race car. Originally built to compete in Le Mans during the 1950s, this 1956 Aston Martin DBR1 represents the very first of five examples that left the factory, and is thought to be the most "correct of all the DBR1s." In a couple of months' time, the legendary race car will be going up for auction at the Pebble Beach Concours d'Elegance, marking the first time a DBR1 has ever been publicly sold.

Built on a lightweight tube-frame chassis, the DBR1 was powered by a more powerful 3.0-liter straight-six than its DB3S predecessor and was a rival to the Ferrari 250 GTO and Mercedes 300 SLR. While this DBR1 didn't win any races at Le Mans, one of its sister cars won the 24 Hours of Le Mans in 1959. That's not to say it doesn't have any significant racing history, however. Sir Stirling Moss drove it to victory at the 1959 Nurburgring 1000 KM, and it also competed in the 12 Hours of Sebring. Other famous drivers who drove DBR1/1 include Carroll Shelby, Roy Salvadori, and Jack Brabham, before it was sold off to Aston Martin Owner's Club President John Dawnay in the 1960s.

After being acquired by numerous car collectors, it's now looking for a new owner. This DBR1 is in immaculate condition for its age and has been fitted with a reproduction engine built by R.S. Williams, but also has its final works engine. RM Sotheby's estimates that DBR1/1 will sell for over $20 million. Not only would that make it the most valuable Aston Martin to ever sell at auction, it could also break the record for the most expensive British car sold at auction set by a 1955 Jaguar D-Type which fetched over $21 million last year.