where was opening scene of sound of music filmed
Mehlweg mountain in Bavaria, Germany
The Sound of Music (film)
The opening sequence of Maria on her mountain was filmed from June 28 to July 2 at Mehlweg mountain near the town of Marktschellenberg in Bavaria. 
wiki:8863158
The Sound of Music (film) [SEP] Filming and post-production
The gazebo scenes for "Something Good" and "Sixteen Going on Seventeen" were filmed on a larger reconstructed set at Fox studios, while some shots of the original gazebo were filmed on the grounds at Schloss Leopoldskron in Salzburg.