1. The first musical number was shot very last, June/July of 1964, and Julie Andrews remembers being bitterly cold and being repeatedly knocked over by the helicopter downdraft. In the meantime, director Robert Wise was hiding in a nearby tree to be able to oversee the scene without being visible in the shot.
2. Christopher Plummer never liked the movie and used to call it The Sound of Mucus. He did record the songs (and even learned to play the guitar!) but they weren't deemed good enough and so he was dubbed. Plummer ate and drank so much during filming to drown his unhappiness that they eventually had to refit his costumes.
3. In the final shot, when the von Trapps are climbing the hills to Switzerland, it is not Kym Karath on Christopher Plummers shoulders. Kym gained a lot of weight during filming and Plummer requested a lighter body double to carry. The real von Trapp family walked to the station and sensibly took the train to Italy. Had they hiked the mountains, they would have ended up in Germany, near Adolf Hitler's mountain retreat...
4. Charmain Carr, who played Liesl, slipped during the first take of the Sixteen Going On Seventeen scene and flew through a pane of glass in the gazebo. But the show must go on - her hurt ankle was bandaged and covered with make-up so she could continue leaping from bench to bench, dancing away with Rolfe (Daniel Truhitte).
5. Kym Karath, who played Gretl, couldn't swim and swallowed too much water when she fell out of the rowing boat, subsequently throwing up all over screen-sister Louisa, Heather Menzies.
6. The real Maria von Trapp does a cameo in the I Have Confidence scene. She is the older of the two women wearing dirndls in the background as Maria walks through a brick archway.
7. Debbie Turner, who played Martha, lost her front teeth during filming and had to wear a false set.
8. Yul Brynner, Sean Connery and Richard Burton were all considered for the role of Captain von Trapp.
9. Doris Day was offered the role of Maria von Trapp but turned it down. Julie Andrews almost turned it down too because she thought the character was too similar to Mary Poppins.
10. Christopher Plummer confessed he had a crush on Julie Andrews and Charmain Carr had a crush on Christopher Plummer.
Here's the cast reunited on The Oprah Winfrey Show:
http://www.youtube.com/watch?v=2VgEma1JGE8&fs=1
http://www.youtube.com/watch?v=BMPKNVyWCCQ&fs=1
http://www.youtube.com/watch?v=RYBp-10WHAA&fs=1
The Sound of Music is released on Blu-ray 8th November.
