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? With the concept’s sleek looks, the name pays homage to both the wild horse of the American west and the legendery P-51 fighter plane of World War 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.