For 60 years, generations of families have delightfully woven spoonfuls of sugar, dancing penguins and supercalifragilisticexpialidocious into their lives, thanks to Walt Disney’s “Mary Poppins.”

In the 1964 film, starring Julie Andrews in her feature film debut, the titular nanny takes young Jane and Michael Banks, the children of her uptight new employers, on a series of magical adventures to add a little more joy to the dynamics of the family.

“It’s entertaining on so many levels, and I think adults can enjoy it as much as kids,” Andrews, 89, told ABC News.

Watch the “20/20” special edition “The Untold Story of Mary Poppins” airing Wednesday, November 27 at 9pm on ABC and streaming the next day on Disney+ and Hulu.

As Poppins takes her young charges on a journey through early 20th century London, they are accompanied by Bert, a charming all-rounder, played by Dick Van Dyke.

“Every minute of that movie was a joy,” Van Dyke, 98, told “20/20.” Everyone had fun, everyone got along. It was just great. I knew it would be a good movie, but it really became a classic.”

However, the road to getting the film made was a long one for Walt Disney. His studio achieved legendary status with the release of the animated classic “Snow White and the Seven Dwarfs” in 1937, but Disney was determined to create a live-action hit.

Disney first became interested in author PL Travers’ Mary Poppins through his daughters, Diane and Sharon, who were captivated by the books. The studio made the first inquiries for the film rights in 1938 and followed suit in 1944, but Travers opposed many of Disney’s ideas for the film.

“Walt Disney wanted to put animation into Mary Poppins. And Ms. Travers wasn’t ready for that,” Becky Cline, director of the Walt Disney Archives, told “20/20.” “She thought it should be a much more serious job.”

She also demanded the right to approve the script, which the hands-on Disney would not allow. This saga inspired its own film – “Saving Mr. Banks” – in 2013, starring Tom Hanks as Disney and Emma Thompson as Travers.

“She was painted as an ancient dragon. And she could be an ancient dragon — and very intimidating, and sometimes quite scary,” Brian Sibley, a writer and friend of Travers, told “20/20.” “I always thought there was some conflict in her because she was quite steely in her ways herself.”

According to Sibley, Travers, who grew up in the Australian outback, was deeply affected by her father’s alcoholism and early death, and her mother’s suicide attempt.

“The trauma of her mother’s suicide attempt is, I think, a crucial turning point in Travers’ life,” Sibley said. “She comforted her sisters by telling them stories about a magical horse.”

Travers’ aunt Ellie helped during this time, with Sibley noting that she was “very much a Mary Poppins character.”

Despite being rejected twice by Travers, Disney had no intention of bringing her character to the big screen. He inquired about the rights again in 1959 and ultimately agreed to pay Travers’ asking price of $750,000. She also served as a consultant, receiving a share of the film’s profits and approval of the script that Disney had previously opposed.

Disney enlisted songwriting siblings Richard and Robert Sherman (who also wrote “It’s a Small World” for the 1964 World’s Fair) to set the film’s tone. They shifted the time period from 1930s London to the 1910s – a more colorful era that suited the music they had in mind.

The Shermans wrote and presented Disney with early versions of four songs, including “Supercalifragilisticexpialidocious.” However, another iconic tune resonated with the studio boss.

“’Feed the Birds’ was always a signature tune for Walt because it talked about (how) small kindnesses can accomplish big things,” Sibley said.

This song was also key to winning over Travers, who met the Shermans during story meetings at Disney’s Burbank studios. Hours of recorded conversations, much of it previously unheard, reveal the tension of these encounters as Travers grappled with reinterpreting her character.

However, the recordings also show that she sang along to “Feed the Birds”, the same tune that turned out to be key for Disney itself.

“She kind of understood that they were onto something special,” Gregg Sherman, Richard’s son, told “20/20.”

With Travers convinced, Disney needed a leading actress to play Mary Poppins. With a subtle push from the Sherman brothers and Disney’s secretary Tommie Wilck, Disney saw Julie Andews in a Broadway production of “Camelot.” He requested a meeting with her after the show and offered her the role.

“And I said, ‘Oh, Mr. Disney, I would… I would be very happy.’ I had never done a movie before. And it was so sweet and charming and sparkling and beautiful,” Andrews told ABC News. “I said, ‘But I can’t do that. I’m pregnant.’ And he said, “Oh, that’s okay. We’ll wait.’ He seemed to have a great instinct for spotting talent.”

When Travers heard about the casting, she called Andrews shortly after the actress gave birth.

“She said, ‘Well, talk to me, I guess you’re going to play Mary Poppins,’” ​​Andrews recalls. “And I said, ‘Well, I just had a baby and I’m feeling a little dizzy right now, Mrs. Travers.’ And she said, ‘Well, of course you’re too beautiful, but you have the nose for it.'”

For Poppins’ friend Bert, Disney turned to the popular actor from the comedy series ‘The Dick Van Dyke Show’.

“When I met Walt, we hit it off right away. We both admitted that we were pretending to be adults and still being kids,” Van Dyke told “20/20.” “I went to his office and he had watercolors of all the scenes from the movie. By the time he was done, I was so excited.”

Hearing the music of the Sherman Brothers was an important moment for Van Dyke.

“Oh, I couldn’t believe it, one tune after another. I was crying,” he said. “It was just the most beautiful thing I’ve ever heard.”

Andrews also liked the Shermans’ work, especially “Supercalifragilisticexpialidocious.”

“The songs had a kind of rumpty-tum vaudeville quality to them,” she said. “And vaudeville was my background as a kid. So I understood that I could probably embrace what Walt had to offer.”

Despite this, Andrews requested a more upbeat keynote song than they had planned for her. Jeff Sherman, Robert’s son, provided inspiration when he received the polio vaccine at school.

“My dad said, ‘Is anyone going to give you a chance at school?’ And I said, ‘No, no, Dad, they had a little plastic spoon. They put a sugar cube in it. And you just ate it,'” he told “20/20.” “My dad looked at me like something was wrong, the wheels were turning.”

The resulting tune, “A Spoonful of Sugar”, gave Andrews the signature song she had hoped for.

Disney also wanted to capitalize on the fantastical nature of the film through the use of stop-motion animation, trick photography and revolutionary audio-animatronics.

The studio used a technique from Ub Iwerks, the legendary Disney animator and inventor who was one of Walt’s oldest employees. This revolutionary new system, called the sodium vapor process, allowed animators to seamlessly combine drawings with the filmed footage.

“All the animation was actually shot in front of a giant screen on a sound stage, without any of the characters in the animation being in front of us,” Andrews said. “So we had to pretend.”

The late Disney animator Frank Thomas, who had worked on animating the dwarfs in “Snow White,” provided the iconic Dick Van Dyke penguin dance sequence.

“Here are his feet flying around and stepping on my penguins. I made them duck and jump and I made them get out of the way any way I could,” Thomas said in a 1984 interview.

Dick Van Dyke remembered seeing the scene for the first time.

“That was so exciting for me when I finally saw it released with the penguins,” the actor said. ‘Because I did all those movements myself. It turned out so well.’

After seeing the finished film at its premiere in August 1964, Travers was still not happy.

“Ms. Travers went to Walt and said, ‘Well, we’ve got to roll up our sleeves. We’ve got a lot of work to do,'” Becky Cline, director of Walt Disney Archives, told ’20/20.’ “And Walt, I think probably with a twinkle in his eye, said, ‘Pamela, the ship has sailed.'”

The film received rave reviews and generated huge profits for Disney. Andrews’ performance won her a Golden Globe for Best Actress, and it was a big hit at the 1965 Oscars.

“The thirteen Academy Award nominations that ‘Mary Poppins’ received were unprecedented at Disney,” Cline said. “Never before, never before has one production received thirteen nominations at Disney.”

The film won five Oscars: Best Actress, Best Special Visual Effects, Best Film Editing, Best Original Score and Best Song (for “Chim Chim Cher-ee”). The soundtrack also spent 14 weeks at number 1 and outsold Elvis and The Beatles that year.

“The critical and personal success of ‘Mary Poppins’ was so huge for Walt Disney. It put him in the pantheon of all these producers and filmmakers who had considered him a cartoonist for so long,” Cline said. “And it proved to them that he was indeed a leading filmmaker.”

The film also spawned a musical that premiered in London’s West End in 2004 (and came to Broadway in 2006), along with a sequel, “Mary Poppins Returns,” in 2018.

Walt Disney died in 1966, aged 65, and PL Travers lived until 1996. She was 96.

Robert Sherman died in 2012 at the age of 86.

“He saw the darkness of the world and dedicated his life to bringing happiness to people,” said his son Jeff.

Richard Sherman lived until May 2024 and died at the age of 95.

“When people find out that my father was one of the Sherman brothers, they are extremely grateful and say, ‘Thank you.’ Thank your dad for writing the soundtrack to our childhood,” said his son Gregg.

Before his death, Richard Sherman made one final musical contribution to his Disney family and to the world. To mark the 60th anniversary of “Mary Poppins” and “It’s a Small World”, he wrote a new verse for the latter.

“And he personally presented it to (Disney CEO) Bob Iger and said, ‘I’d like to present this to you as my final contribution to the studio,’” Gregg Sherman said.

That verse, Sherman said, is a prayer for peace.

“Mother Earth unites us in heart and mind / And the love we give makes us human / Through our vast wondrous land / When we stand hand in hand / It’s a small world after all.”

Disney is the parent company of ABC News.