The film’s Von Trapp family was led by Julie Andrews and Christopher Plummer (center). (photo courtesy of IMDb)

It has been six decades – officially – since “The Sound of Music” was released in movie theaters. Based on the hit Broadway show, the movie is a fictionalized account of the real-life von Trapp family, who fled Austria after the Nazi invasion. While a heavy chunk of the movie was shot on location in Salzberg, all of the interiors were shot right here in Los Angeles, at the Fox Studios lot in Century City.

The movie focuses on Maria, the novice nun turned governess of the von Trapp children. The Von Trapp’s mother has died, leaving them in the charge of their strict father, Captain von Trapp. Maria brings music back into the household, and the captain softens. She and the captain fall in love, of course, just as the Nazis take over Austria.

In celebration of the movie’s diamond anniversary, several events have marked the film’s iconic place in culture, including the annual Hollywood Bowl sing-a-long and a theatrical rerelease. For actresses Angela Cartwright, Debbie Turner and Kym Karath – who played Von Trapp children Brigitta, Marta and Gretl when age 11, 7 and 6, respectively – its multi-day return to the silver screen didn’t last nearly long enough.

“I think people today want to go to the theater and see a movie that makes them feel good like this,” Cartwright said. “There’s enough stuff on television that’s … horrific stuff, but [people want] to go to a movie with your family and to enjoy the music and the whole thing.”

Turner said that the film’s limited theatrical rerelease had been so successful, that friends were unable to get tickets.

“It sold out in like a day,” she said.

“Are you listening, Disney?” Cartwright cracked, subtly imploring “The Sound of Music” rights holder to put the movie back in theaters again. The movie is also available in a special 4K 60th anniversary edition blu-ray, as well as digital download.

These former child stars landed their roles in the movie after an extensive search in which thousands were considered – just about every young performer in Hollywood was auditioned.

“We went, we met with them, and then we got a call back, and we had to sing,” Cartwright recalled. “I think I went back twice, and then they screen tested me for Brigitta and Louisa with a blonde wig. I’m really glad I didn’t have to wear a blonde wig through the whole movie.”

The cast rehearsed on the Fox lot for three months and recorded the soundtrack.

“They built faux sets. [They] were just plywood,” Cartwright said. “We had a mattress on the floor where we practiced ‘My Favorite Things.’ We had plywood stairs they built for ‘So Long, Farewell.’”

While professionals were used for the closeups, the children also became expert puppeteers for the elaborate “The Lonely Goatherd” puppet theater scene. Turner and Karath, slightly younger than the rest of the crew, were in charge of the scene’s backdrops and pushing in various scenery.

“They didn’t let us do the hard stuff,” Turner laughed. “It was very hard for me to push the prince. The prince was heavy.”

The movie filmed on location in Austria from March to July of 1964, then the company relocated to Century City and continued production through August. Though over half of the film was shot on one end of the globe and the other half was shot on the other, the cast continues to marvel at how well the scenes – filmed months apart – blend together. This, they explain, was the true magic of Old Hollywood at work.

“They had that down,” Karath said. “Within the studio system, they could do anything and make it look [real]. I mean, they were actually incredible given how little comparative technological expertise they had.”

Kim Karath, Angela Cartwright and Debbie Turner portrayed Gretl, Brigitta and Marta in “The Sound of Music.” (photo courtesy of IMDb)

The trio, along with their other movie siblings, have maintained a close bond even all these years later. While the older von Trapp daughter portrayers Charmian Carr and Heather Menzies both died several years ago, Cartwright, Turner and Karath remain close to their on-screen brothers Nicholas Hammond and Duane Chase.

“It was brilliant casting,” Karath said. “I have to say, [they] put together a family … somehow, we became family. I mean, [Wise] couldn’t have envisioned that, but somehow, we did. And I still see the family resemblance between all of us.”

Decades later, “The Sound of Music” endures as the one of the most popular films ever made. Its music is almost synonymous with the American songbook, with tunes such as “My Favorite Things,” “Do-Re-Mi” and “So Long, Farewell.” But it’s the core message of the film that its stars credit with its continued relevance.

“It’s like alchemy. There’s a magic that happens, and it’s a combination of things that make something be magical,” Karath mused. “But it’s based on a true story. So it’s cemented by this … true story of a very courageous family that basically made the right choice in the face of Nazism, and they didn’t have to. They weren’t Jewish. They just couldn’t stomach what it was that there was going on.”