This San Francisco museum is home to the earliest known drawing of Mickey Mouse

SAN FRANCISCO (KGO) -- In the Presidio of San Francisco, The Walt Disney Family Museum is home to thousands of artifacts and memorabilia of the life and career of Walt Disney. Among the letters, photos, videos, miniatures, animation cels, and countless other forms of Disney keepsakes, the museum's most prized possession is the earliest known drawing of Mickey Mouse.

"This is the ultimate piece that we have in the collection, definitely," says Marina Villar Delgado, Director of Exhibitions and Collections at The Walt Disney Family Museum. "This is a sketch, the first idea. (This is) the beginning of Mickey."

The drawing was done in 1928 by Ub Iwerks and the first idea for Mickey's name was "Mortimer Mouse."

"Lilly, Walt's wife, told him, 'this is not a name for a mouse,'" Delgado says. "Let's call him Mickey Mouse."

The Walt Disney Family Museum is a 501(c)(3) nonprofit organization founded by Walt and Lillian's daughter, Diane Disney Miller. The museum features contemporary, interactive galleries with state-of-the-art exhibits narrated in Walt's own voice alongside early drawings, cartoons, films, music, a spectacular model of Disneyland, and more.

But the collection area of the museum, where all items are received and cataloged, is home to some of the most rare and fragile items.

"We keep all the artwork here," says Delgado. "This is where we keep the humidity and temperature perfect for the objects to be safe and secure."

The museum's goal is to inform present and future generations about Walt Disney the person and through his story, to inspire them to heed their imagination and pursue their goals.

"Most of the objects in the collection come from the family," Delgado says.

When items come to the museum, they are received by Delgado and her team, where they are cataloged and photographed.

But perhaps no item is more important than the Mickey sketch.

"This is the beginning of everything," Delgado says. "This piece was rediscovered in the 1990s in the family vault."

She adds, "The original drawing is on view for up to three months, and then we have another piece, we call 'clean-up.'"

The "clean-up" is an exact replica of the drawing that was made from the original sketch at the time it was produced. The original piece includes marks and notes, including a large circle, inked in blue graphite, symbolizing the final selection for Mickey's form.

"We have many requests from other museums to travel this piece," Delgado says. "It never travels. The only place you can see the original artwork, this original Mickey, is at The Walt Disney Family Museum, at the Presidio in San Francisco, in Gallery 2B."

The museum's standard operating hours are Thursday through Sunday from 10:00 a.m. to 5:30 p.m. For more information visit here.