|Reader's Digest New Treasury for Young Readers. Pleasantville, New York: The Reader's Digest Association, 1963.
I discovered this story published as The "Impossible" Race from Peking to Paris by J.D. Ratcliff in the Reader's Digest book cited above, and originally published in The Kiwanis Magazine in 1957.
According to Ratcliff, the race was originally proposed by the French newspaper Le Matin. Drivers would have to travel an estimated 8 to 10,000 miles between the two cities. Entries included two French De Dion-Boutons, a Dutch Spyker, a six-horsepower French Contal three-wheeler, and finally a powerful forty-horsepower Itala carrying Prince Scipione Borghese, his chauffeur Ettore Guizzardi and the Italian journalist Luigi Barzini. The race began on June 10, 1907, with the cars moving out of Peking. Challenges included rain, soaking the occupants of the open cars and turning the roads (such as they were) into muddy morasses. Then came the mountains in northern China, followed by the Gobi desert, then three thousand miles of Siberian mud and rotten, wooden bridges, and occasional trips on the railway tracks with close calls with oncoming trains. At one point, the gasoline that was supposed to have been brought to a storage point was not there, but the Borghese party discovered that for some unknown reason a local shop had a large supply of benzine. Tanks were filled and the car soldiered on, "smoking like a coke oven." Finally, at 4 p.m. on August 10, 1907, 61 days after leaving Peking, the Itala limped into Paris. The only other cars to complete the race were the two De Dion-Boutons, which didn't arrive until August 30th.
In 1957, Luigi Barzini, Jr., the son of the journalist who had accompanied the first race, sought permission to cross Soviet Russia by car in a trip from Peking to Paris. The Soviets declared the trip to be "impossible."
For more information, see the Wikipedia entry.