When Bonhams announced the sale of Juan Manuel Fangio's 1954 Grand Prix-winning Mercedes W196 in March, the storied machine was expected to fetch around $7.5 million. Today, when the auctioneer's hammer fell, the Mercedes became the most valuable motor vehicle ever sold at auction, smashing the previous record with a final price of $29.6 million.

The Mercedes-Benz W196 took the legendary Fangio to his second of five world championships, winning the '54 German and Swiss Grand Prix in the process. The beautiful machine sports a 2.5-liter straight eight motor, and brought technologies such as fully-independent suspension and fuel-injected engines to Formula One. But perhaps the most amazing tale in the car's history is not its on-track success, but that it was forgotten about in a warehouse for 30 years. According to Bonhams, the owners tested the motor one last time prior to putting it in storage, where it sat until recently.

That sequester likely powered the record price; today's high-dollar car collectors value not just uniqueness but authenticity, much in the same way art collectors want originals rather than prints. Having Fangio's championship car in a broken-down but untouched state means far more to these bidders than if someone had tried to rebuild and repaint it three decades ago — and likely lost much of the look or original mechanical parts of the car in the process.

The previous auction record was set in 2011, when a Ferrari Testarossa prototype brought in over $16 million. The final bid was for 17.5 million British pounds, or $26.4 million — the remainder came from the auction house's buyers fee.

Not only is it the most valuable car ever sold at auction, but it becomes the most valuable Formula One car ever sold, as well as the most valuable Mercedes-Benz. It's still shy of the supposed record of about $40 million, which the Mullin Museum paid for a 1936 Bugatti in 2010. No word on the name of the lucky buyer, nor what they plan to do with the $29 million hallway decoration, but Bonhams hopes the buyer restores it to run next year at the 60th anniversary of Fangio's win.