The unidentified owner's grandfather was the original buyer of the 1928 Mercedes-Benz S-Type Sports Tourer.
The car still runs well, even though it has sat unused since the 1950s..
The gunmetal grey car has never been restored.
Able to hit 100 miles per hour, the the S-Type was one of the world's fastest cars when it was first manufactured in Germany.
The one-of-a-kind car is set to go under the hammer at Bonhams’ Goodwood Revival auction in London on Sept. 15
This 1928 Mercedes sat untouched in a garage for more than 60 years. It could fetch more than $2.5 million at auction.