The annual Pikes Peak International Hill Climb is the second-oldest major motorsport event run in the United States, after the Indianapolis 500.
With its 12.4-mile course boasting 156 turns and an elevation gain of more than 4,000 feet, it's also one of the toughest.
And this year, electric cars dominated the race, placing first and second overall.
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Pending official approval of the results, this is the first time an electric car has won Pikes Peak outright.
The winning car was a purpose-built eO PP3 from Latvian engineering firm Drive eO.
Driven by Pikes Peak veteran and professional drifter Rhys Millen, the car's 9:07.222 time was not only the fastest this year, but also a record for electric cars at the hill climb.
Rhys Millen and the eO PP03 at the 2015 Pikes Peak Hill ClimbEnlarge Photo
Power is supplied by a 50-kilowatt-hour lithium-ion battery pack, and the entire car weighs just 2,645 pounds (sans driver).
Millen actually completed his record run without full power.
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Nonetheless, the car still had enough juice to beat the previous electric-car record of 9:08.188 set by Greg Tracy in a Mitsubishi i-MiEV Evolution III last year.
The overall record for Pikes Peak is still the 8:13.878 set by rally driver Sebastian Loeb in 2013, behind the wheel of the Peugeot 208 T16 Pikes Peak racer.
Finishing second place for 2015 was another electric car, the Tajima Rimac E-Runner Concept One, driven by its namesake, Nobuhiro "Monster" Tajima.
Electric racer to be driven by Nobuhiro ‘Monster’ Tajima in 2015 Pikes Peak Hill ClimbEnlarge Photo
His car was built by Croatian automaker Rimac, creator of the 1,088-hp Concept One electric supercar.
A purpose-built single-seater like the eO PP3, the Rimac Pikes Peak racer has four electric motors that produce a combined 1,475 hp.
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That power is sent to each wheel without any gearboxes or differentials. Each motor is connected to a wheel with a chain system, designed to save weight and space.
Due to foul weather conditions at the summit, the finish line was moved further down the mountain partway through the race.
Because of the shorter track length completed by drivers that ran after the race, the results remain provisional.