A Special Edition of "20/20? Featuring Interview with Julie Andrews in Salzburg Airs Wednesday, March 18 at 10 p.m., ET on ABC

ABC News Anchor Diane Sawyer takes viewers on an incredible journey to Austria with Oscar-winning actress Julie Andrews, exploring the mystery of ' The Sound of Music' story that captured the world's attention and endured for so long. With unprecedented access, Sawyer goes behind-the-scenes to show viewers what happened beyond the frame in those famous movie scenes and re-trace the steps of the real von Trapps who defied the Nazis and were forced to leave the country they loved. " The Untold Story of 'The Sound of Music'" is a one-hour primetime special edition of " 20/20" airing Wednesday, March 18 at 10 p.m., ET on the ABC Television Network.

When the film premiered, the United States was facing the Vietnam War and the bloodshed in Selma. Audiences of all ages turned to 'The Sound of Music' as an affirmation of hope and possibility. Sawyer explores this context and its impact that still resonates today across the cultural spectrum, as recently as, Lady Gaga and Andrews at the 2015 Oscars.

In the special, Sawyer and Andrews re-create the magic. Andrews opens up about her real life and her fictional one as Maria. ABC travels to landmarks including the meadow, fountain, gazebo, Mirabell Gardens and St. Michael's Church, among others. Andrews talks about her favorite and least favorite songs, and Sawyer combs through photographs and video from the set and of the real von Trapps and meets some of the many tourists who trek annually to the town of Salzburg.

For the first time, Andrews ventures to a part of Austria she's never been - the house where the real Maria von Trapp lived - and goes with Sawyer to the train station the family used to make their escape. Mother Abbess of the Nonnberg Abbey emerges from those sacred walls to tell Sawyer what she really thinks about the film. And Christopher Plummer, who played Captain von Trapp, shares his insight on the movie and his special bond with Andrews.

David Sloan is the senior executive producer, Mark Robertson and Matt Lombardi are senior producers and Eric Noll is producer on this special.

- ABC -