The Bugatti Type 41 Royale Kellner is a classic luxury car that Automobiles E. Bugatti made between 1927 and 1933. The company’s founder, Ettore Arco Isidoro Bugatti, wanted to manufacture 25 of them for royalty, hence “Royale” in the moniker. Today, the Bugatti Royale Kellner is one of the world’s rarest and most expensive classic cars — they typically go for millions at auction. For example, in 1987, one Royale sold for $9.7 million.

The Bugatti Royale Kellner, 1 of the world’s most expensive cars, was a fiscal failure

Imagine being one of the most notable automobile designers of your time and learn of unfavorable criticism about your cars. How would you react? Most people in similar situations wouldn’t care about random criticism. But that wasn’t the case with Ettore Bugatti. Though the history is sort of vague, it’s said that he took exception to criticism from a British woman who said his car designs resembled those of the British luxury automaker Rolls-Royce. In response, he built the Type 41 and attempted to market it to royalty and the ultra-wealthy.

It didn’t work out too well for Mr. Bugatti.

He designed the Royale to be one of the world’s most luxurious cars at the time. But eventually, he discovered not even European royals were interested in purchasing such an expensive model. Back then, the Royale cost $43,000 — about $632,790 today when adjusted for inflation. On top of that, Mr. Bugatti led with his emotions, which resulted in his selling only a fraction of the number expected. For example, he canceled a Royale order for King Zog of Albania because he didn’t like how the leader ate.

Other possible factors that led to the Bugatti Royale’s failure include four-year delivery waits and the Great Depression. Even the wealthiest people back in those days became frugal about spending money on such luxurious items. Of the 25 or more models Bugatti had planned to build and sell, the company produced only six, excluding the prototype: the Coupé Napoleon, Coupé de Ville Binder, Cabriolet Weinberger, Limousine Park-Ward, Kellner, and Berline de Voyage. A crash totaled the prototype.

The Bugatti Royale Kellner is the only model not in a museum

The type of collector willing to spend millions on a car is typically not the type who sells vehicles they collect. This has been particularly true when it comes to Bugatti Type 41 collectors. Five of the six Bugatti Royale Kellner coupes reside in museums around the globe. The Kellner coupe is the only model owned and possessed by a private owner, whose identity is unknown. However, Swiss broker Lukas Huni has displayed it at various classic car shows around the world.

According to Gizmodo, it’s one of the nine rarest cars in the world. It sold for nearly $10 million at auction in 1987.

Not only expensive but also large

Baby Boomers are known for saying, “Cars in my day were built like tanks.” Well, the Bugatti Royale Kellner was made before their generation and definitely built like a tank. Constructed around a single 4.6-foot-long by 3.6-foot-high block, the Royale’s engine had a 12.7-liter displacement. To put that into perspective, some tanks used during World War I and World War II, such as the Renault FT, had only a 4.5-liter engine. Stronger tanks, like the T-34, used a Kharkiv model V2 engine with a 38.8-liter diesel engine, but that wasn’t until after WWII.

According to Motor Car, the engine had eight cylinders bored to 125 mm (4.9 inches) with a stroke length of 130 mm (5.1 inches). This meant the displacement in the Type 41’s engine was more than the Type 40’s entire engine size. A centrally positioned single overhead camshaft drove three valves per cylinder. Because Mr. Bugatti had designed airplane engines, it’s no surprise the Bugatti Royale Kellner coupe’s engine was based on an aero-engine design devised for the French Air Ministry. The only difference between the two was the configuration.

Engine technology has come a long way — the Bugatti Royale’s engine produced only 275 to 300 hp.