A rare, and enormous, 1950 General Motors Futurliner bus sold at Barrett-Jackson's Scottsdale auction Saturday for $4 million.
The money will benefit a charity for military members and their families.
The bus sold as part of the automotive collection of Arizona-based real estate developer Ron Pratte. He bought the bus in 2006, also at a Barrett-Jackson Scottsdale auction, for roughly the same amount.
The bus was one of 12 built by GM (GM) to lead its Parade of Progress tours in the 1940s and '50s. Starting shortly after the 1939 New York World's Fair, these events showed off General Motors products and concept cars at events around the nation.
Not long after they got going, the events were stopped for World War II. Years later, the tours started up again and the buses underwent major modifications.
Despite their enormous size, these buses could carry only three occupants including the driver. The sides opened outward to reveal a stage.
The buses were originally powered by two-stroke diesel engines, and after 1953 they were fitted with 145 horsepower six-cylinder gasoline engines.
The driver's seat was 10 feet off the ground. Parade organizers had to carefully plan routes to avoid low bridges or other obstacles. Eight tires held its 30,000 pound weight.
The tours were permanently shut down in 1956, and most of the buses were modified for other uses.
Today, nine of the vehicles survive and only three -- this one included -- have been restored and returned to their original Parade of Progress configuration.
Proceeds from the sale of the Futurliner bus are being given to the Armed Forces Foundation, a nonprofit that serves military service members, veterans and their families.