A unique and spectacular 1939 General Motors Furturliner is up for sale in Reno on August 6.
It will cross the block at the Hot August Nights car show, with bidding facilitated by the Motorsport Auction Group.
It's one of 12 models produced for GM's Parade of Progress, which toured the US in 1939 outlining the new technologies that could arise in the future.
Only nine are known to still exist.
The parade was intended to tour throughout the 1940s, but the second world war put paid to the company's plans and all of the vehicles were auctioned off.
This example features a display titled "Power for the Air Age". It's enormous, measuring around 33 feet long and weighing over 12 tonnes.
It last sold for $247,000 in 2011, in unrestored condition.
Since then it has been painstakingly restored by Kindigit-it Designs.
While there is no estimate available, another restored Futurliner sold for $4m last year.
Auction house spokesman Frank Yaksitch says: "If you're a car collector, this is the Mack Daddy."
Yaksitch said that he had hopes the winning bidder would be local to the area: "If [Reno casino magnate] Bill Harrah were alive today, he would be our number one bidder.
"This would be something that would fit his collection and would be very desirable to him as a collector.
"We all know he's not here, but his legacy is.
"There's a chance that somebody here in town who can afford such an automobile steps up and keeps it right here."
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