These intriguing concept cars were futuristic, but never made it to the production line

Buick Y-Job. Introduced by General Motors in 1938, the vehicle had hidden headlights and electrically powered windows.

XP-21 Firebird I (1953).  GM's rocket-styled XP-21 Firebird 1 was the first gas turbine automobile built and tested in the United States.

Buick XP-300 (1951). The Buick XP-300 had a 335-horsepower V8 engine that could run on either gasoline or methanol and may have been able to reach 140 mph.

Alfa Romeo BAT (1953).  Created by car designer Giuseppe Bertone, the car sported massive rear bumpers and curved fins.

Lincoln Futura (1955).  The inspiration for the Batmobile, the Futura was created by Bill Schmidt, Lincoln-Mercury Division's chief stylist, after he got the idea watching sharks and other sea life while on vacation in the Bahamas.

Ford La Tosca (1955).   The vehicle had retractable headlights and could be maneuvered by remote control.

Buick Centurion (1956). Its body was made from fiberglass, and the interior looked like an airplane cockpit.

Ford Nucleon (1958). Demonstrated as a scale model, the vehicle was to be powered by a small nuclear reactor in the rear of the vehicle and use a steam engine powered by uranium fission, a system similar to those found in nuclear submarines.

GM-X Stiletto (1964).  Debuted at the 1964 New York World's Fair, the vehicle had no doors. You entered the vehicle through a hatch.

Alfa Romeo Carabo (1968).First shown at the Paris Motor Show in 1968, the Carabo is the predecessor of the Lamborghini Countach, and its featured scissor doors would have a major design impact on cars in the years to come.

Ford Gyron (1961). Shown at the 1961 Detroit Auto Show, the two-seater Gyron design was similar to that of a motorcycle, steadied by gyroscopes.

Mercedes-Benz C111 series (1969). The C111-I's Wankel engine generated 280 horsepower, fast enough to go from zero to 62 mph in five seconds.

Ford Seattle-ite XXI (1963). The six-wheeled concept car featured interchangeable fuel cell power units and body shells; computer navigation and mapping.

Lancia Stratos Zero (1970).  The car, which appeared in the 1988 Michael Jackson film "Moonwalker," was just 33 inches in height, and you entered the Zero by lifting up the windscreen since there were no doors.

Vauxhall SRV (1970).  The Vauxhall SRV (SRV stands for styling research vehicle), was a sleek four-door, four-seat sports car that debuted at the London Motor Show in 1970.

Maserati Boomerang  (1972).  The Maserati Boomerang had no speedometer gauge and many of the buttons and dials in the interior were not labeled.

Lancia Sibilo (1978).The curious interior, which had only a few features on the dashboard, failed to match the Lancia Sibilo's eye-catching exterior.

Citroën Karin (1980). The driver seat of the all-beige Citroën Karin was in the middle of the three-seater vehicle and slightly forward from the passengers.

Pontiac Banshee IV  (1988). The driver's seat resembled an astronaut's cockpit.

BMW Nazca C2 (1991). The vehicle frame of the racetrack-oriented C2 was made from carbon fiber, unusual for the early 1990s, and weighed only 2,204 pounds.

Peugeot Moovie (2005). The Moovie's somewhat minimal concept considered how smart cars would look in the future, with big round doors and space for two in the car's cockpit.

Citroën Hypnos (2008). A colorful midsize crossover, the Citroën Hypnos had a red gauge, orange-yellow-green the front seats, and blue and purple rear seats.

Tang Hua electric vehicle (2008). The entire vehicle, which made its debut at the North American International Auto Show in Detroit in 2008, was made of fiberglass.