1957 was a special year for two reasons - launch of Sputnik the world's first satellite and second was the Launch of Cadillac Eldorado Brougham.
The Cadillac Eldorado Brougham was the most expensive car from GM even expensive than Rolls Royce silver cloud of 1957.
So Whats special about the car - World's first car with Memory power seats , air suspension and many more features - See the video below
Cadillac Eldorado Brougham -- "The Cadillac of Cadillacs"‏ - YouTube
( Source - Wikipedia.org and YouTube.com)