1965’s The Sound of Music opens with a long sweeping shot, flying over endless green Alpine meadows and mountaintops, with the sun shining and the lakes in the distance glistening. As the music swells to a crescendo, the camera finally fixed on our lead character, Maria von Trapp, who effortlessly segues into the enormous opening number.

As opening scenes go, it’s one of Hollywood’s most effective and most famous. But it certainly wasn’t easy to shoot.

The grand opening shot of The Sound of Music was filmed from a camera mounted on a helicopter, flying over the mountains around the town of Marktschellenberg, in Bavaria, Southern Germany. This being the German Alps, the changeable Alpine weather proved a problem more than once during filming, and the director, Robert Wise, had to wait for suitable breaks between rainstorms to shoot the opening number in blazing Alpine sunshine.

“It poured with rain, and we were freezing cold on top of those mountains at times,” Andrews explained in an address to the American Film Institute in 2007. “We would dash out from under our tarpaulins and warm blankets and try to get the shot.”

But the weather was less of a problem compared to the helicopter itself. “This was a jet helicopter,” Andrews explained, “and the downdraft from those jets was so strong that every time … the helicopter circled around me, the down draft just flattened me into the grass. It was fine for a couple of takes, but after that you begin to get just a little bit angry…

And I really tried. I mean, I braced myself, I thought, ‘It’s not going to get me this time.’ And every single time, I bit the dust.”