Car: 1931 Bugatti Type 41 Royale Kellner
Number produced: 6
Price at auction: $9.8 million
During the first half of the 20th Century, a French company named Bugatti made some of the most exclusive, expensive, luxury-laden and fastest automobiles on the planet. Designed by the eccentric Italian engineer Ettore Bugatti, their cars featured light bodies, huge engines and exotic styling. Like a lot of European car companies, however, they weren't able to survive World War II.
Bugattis were often exercises in automotive insanity, and the 1931 Type 41 Royale Kellner was no exception. The car featured a massive 12.7-liter straight-eight engine, one which remains the largest engine ever put in a privately-sold automobile. The rest of it was big, too -- the wheelbase was more than 15 feet (4.6 meters) in length, and its price tag was far beyond the buyers of the Great Depression era when it was built [source: Forbes].
Only six were constructed, and this one was hidden behind a false wall to save it from the raging war in Europe. In 1987 it was sold at auction for nearly $10 million.
Today, the Volkswagen Group has revived the Bugatti marque and built the record-breaking Veyron, a car capable of speeds of more than 250 miles per hour (402.3 kilometers per hour). The insanity lives on.