The 250 GTO in question is chassis number 3505GT and was built specifically for the legendary Stirling Moss. While Moss never actually ended up racing the car (a career-ending crash in April of 1962 prevented him from getting behind the wheel), it has a fairly significant race history with several wins. 3505GT also competed in the 1962 24 Hours of Le Mans, although it ended the race with a DNF. The car stands out among the other 250 GTOs thanks to its unique lime-green livery.
Amazingly, the price of this particular car has increased tenfold since 1996, when it was purchased for $3.5 million. From there the car has changed hands a few times, with the most recent owner, a Dutch businessman, purchasing it for $8.5 million about a decade ago. The 250 GTO's newest owner, car collector Craig McCaw, earned his fortune by selling a telecommunications company to AT&T for $11.5 billion back in 1993.
We most recently saw the car at the Pebble Beach Concours d'Elegance last year, where it was displayed as part of the 250 GTO's 50th anniversary celebration. You can see photos of the car at Pebble Beach in the gallery above.