On the evening of June 6, 1933, motorists crowded into a parking lot on Crescent Boulevard in Camden, New Jersey for the first ever drive-in movie screening. And with that, the drive-in theater craze was born.

1964: Ford introduces the Mustang at the New York World’s Fair. It becomes an instant hit and an icon that alters the automotive landscape, giving rise to one of the most successful — and most uniquely American — automobile genres: the pony car.

The Ford Mustang was born of the simple idea that putting a back seat in a sports car would be a great idea.

The idea came to Lee Iacocca and Donald Frey in the early 1960s as the country was being overrun by European sports cars. Everywhere you looked you saw Alfa Romeos and MGs and Triumphs that dripped oil. Even French cars that would draw peals of laughter today were popular back then.

The two Ford execs saw a vast market literally rolling before their eyes, and, according to legend, the notion of a sports car with a back seat was one of those “ah-hah” moments. If Ford could dilute the European ethos just a bit by making the cars a bit more practical and a lot more affordable, Iacocca figured, the company would sell a few thousand.

He was right, but boy was he wrong. Ford didn’t sell thousands of them. It sold millions of them.

They sold 22,000 on the first day.

The Mustang was more than a success. It was a phenomenon. Ford sold 1 million in the first 18 months, making the Mustang its most successful launch since the Model A.

The pony car is easy to define. It was small by Detroit standards, with sporty styling. It had a back seat for your kids and a usable trunk for your stuff. And the rear wheels were driven by an engine — ideally a big V-8 — mounted up front where God and Henry Ford intended.

Pony cars may not have had the finesse of a European sports car, but they made up for it with brute force. A small-block V-8 can make up for a multitude of handling deficiencies.

The Mustang was successful like the Beatles were popular. Ford figured it would sell around 100,000 in the first 12 months of production. It sold 10 times that number in the first 18.

That success was not lost on the rest of Detroit, and everyone was cranking out pony cars by 1967. General Motors introduced the Chevrolet Camaro and its kissing cousin, the Pontiac Firebird. Ford offered the more upscale Mercury Cougar. Chrysler released the Challenger. Even AMC — google it, we’ll wait — got into the act with the Javelin.

Everyone had a favorite, and even now loyalists occasionally come to blows over which one was best. Countless bets have been made and races staged in displays of testosterone and bravado that would make Dr. Freud sit down for a cigar and a good long think.

And that was just in the parking lots and streets. Things really got wild when the automakers got in on the act, bringing in drivers like Dan Gurney and George Follmer and Mark Donohue to show who built the best car. The contest grew so heated it gave rise to a pony-car–specific racing series called Trans Am. (The car was named after the series, not the other way around.)

We’re inclined to give the award to the Mustang, if only because Steve McQueen drove a ’68 fastback in the most famous chase scene in cinematic history, that amazing dash through the streets of San Francisco in Bullitt.

The Mustang also gets the nod for sheer longevity. Oh sure, you can get a new Camaro that looks like a vintage Camaro, or a new Dodge Challenger that looks like a vintage Dodge Challenger.

But the Mustang is the only pony car to remain in continuous production since its introduction 45 years ago.

Ford has sold more than 9 million worldwide.