More than 50 years ago, a group of designers put pencil to paper with a new kind of sports car in mind. Lee Iacocca wanted something fresh, sporty, and easy on the wallet—something for the emerging market of teenagers who simply wouldn’t settle for their grandma’s Fairlane.

What they created turned a lot of heads, but never made it past the concept stage.

The drawings and early models featured sleek lines, pointed ends and a road-hugging frame. At the time, it looked like a vehicle for a new era (or from another planet).

And what to call it? First known as the Special Falcon, the Mustang I moniker was finally selected from a big pool of names—the Cougar, the Bronco, the Puma, the Cheetah, the Colt, the Torino, and even the T-Bird II.

Of course, the Mustang went through some major revisions before the pony car we know and love rolled off the assembly line in 1964. But even the most dedicated Mustang fans may not know what the very first Mustang looked like as a concept car. So we pulled some rarely seen pics from the archives to show it off.

Take a peek at the Mustang’s early sketches, pics of the first engineering team, and even interior shots of the prototypes. Then, share your comments below: What features from the Mustang I were your favorites? Do you like the 1964 ½ better? Should we borrow a few of these style elements for the next iteration of the Mustang? Tell us what you think!