Mickey Mouse may seem pretty spry, but he made his first public appearance to test audiences 89 years ago this week. No, the cartoon wasn't the much-beloved Steamboat Willie—it was Plane Crazy, a six-minute silent short that was made in a matter of weeks. Here's what you need to know about Mickey's high-flying debut.

1. IT WAS A REVENGE CARTOON.

In 1927, Walt Disney and his partner, Ub Iwerks, had recently lost the rights to Oswald the Lucky Rabbit—a popular character they had created—to Charles Mintz, a producer and distributor for whom they had been making cartoons. To add insult to injury, Mintz also hired most of the animators out from under Disney and Iwerks. Determined to come up with something just as good, the duo worked on the short that would become Plane Crazy while simultaneously finishing their last three Oswald shorts for Mintz.

2. THE PROJECT WAS KEPT SECRET FROM THE REST OF THE ANIMATORS.

To keep the project top secret, Iwerks drew in an isolated room away from the other animators working on the last Oswald cartoons. He prided himself on his breakneck pace, often completing as many as 700 drawings a day. Other animators who had stayed loyal to Disney worked behind high black curtains to prevent the “traitor” employees from seeing.

3. THE CELS WERE HAND-INKED IN DISNEY’S GARAGE.

When it came time to ink Iwerks’s drawings onto cels, Walt, his wife Lilly, and two of his sisters-in-law huddled together in Disney’s garage and did them by hand. They went back to the studio and photographed the cels late at night when no one else was there.

4. THE SHORT PARODIED THE CHARLES LINDBERGH CRAZE.

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Disney decided on a plane-themed cartoon for Mickey’s debut to take advantage of the public’s love of aviator Charles Lindbergh. Lindbergh had made his famous transatlantic flight just the year before.

5. IT HAD A VERY LIMITED NUMBER OF PUBLIC SCREENINGS.

Not many people got to witness Mickey’s first appearance, and the lucky few who did had no idea that they were witnessing history. On May 17, 1928, a Los Angeles theater showed Plane Crazy to test audiences for one day only. Walt sat in the back of the theater and monitored the audience’s response. It was nearly unanimous: Everyone loved the little mouse.

6. PLANE CRAZY’S FAILURE INSPIRED WALT TO GET IN ON THE TALKING PICTURE CRAZE.

Though Mickey and pals tested really well with audiences, the silent short failed to pick up a distributor. The Jazz Singer had come out the year before, and in a flash of inspiration, Walt decided that synchronized sound was the future of cartoons.

7. IT WAS THE FIRST MICKEY MOUSE CARTOON TO BE MADE, BUT THE THIRD TO BE RELEASED.

Rather than apply sound to Plane Crazy retroactively, Disney decided to try the synchronized sound technique on the short the team was currently working on—Steamboat Willie. Mickey’s stint as a riverboat pilot was released, to much fanfare, on November 18, 1928. It was only after that success that Disney and Iwerks went back and added sound to Plane Crazy and The Gallopin’ Gaucho, another silent short they had worked on prior to Steamboat Willie. As a result, Plane Crazy was actually the third Mickey short to be released even though it was the first to be completed.

8. THE SHORT WAS ALSO MINNIE’S DEBUT.

Of course, much is made of the fact that Plane Crazy is technically Mickey’s first appearance, but it’s also Minnie’s debut, which makes them sweethearts from the get-go. (Though if you actually watch the short, she’s not exactly thrilled about the prospect just yet.) It also marks the first appearance of Clarabelle Cow.

9. PRODUCTION WAS A BARGAIN.

According to Disney records, the entire short—minus the sound—was made for a mere $1772. That’s roughly $25,339 in 2017 dollars.

10. WALT’S KIDS WEREN’T IMPRESSED.

Though Plane Crazy was groundbreaking at the time, by the time Disney’s children saw the first Mickey Mouse cartoon later in life, they were unimpressed. The kids were reportedly “astonished” by how crudely drawn he was, with sticks for arms and legs and a circular torso.

11. YOU CAN STILL SEE PLANE CRAZY AT DISNEYLAND.

You can still get a taste of what it might have been like to see Plane Crazy in a theater back in 1928. The Main Street Cinema at Disneyland still runs six old Mickey Mouse cartoons today: Plane Crazy, Steamboat Willie, The Moose Hunt, Traffic Troubles, The Dognapper, and Mickey’s Polo Team.

Or, you can watch it right here: