Thanks everyone! Here are a few more...
The Neue Rathaus in Munich:
The town of Mondsee, Austria:
The Sound of Music tour was really fun. We didn't see the cemetery, which, according to the special features on the DVD, was actually a set recreated in Hollywood. We saw the lake that they fell into (which is also where the terrace scenes were shot, but only the parts that face away from the house), we drove by the house, we saw the gazebo, we saw Nonnberg Abbey from down a hill (we wouldn't have been allowed to go in)... We also drove by the foot bridge in Salzburg that they run over, and the tour itself ended near the Mirabell gardens, which is where a good chunk of the Do-Re-Mi scene was filmed. We also drove into the mountains, and they pointed out some of the mountains featured in the opening scene, and into the town of Mondsee to see the church where Maria and the Captain were married. My sister and I brought my portable DVD player on the train with us, and we watched the movie on the way back to Munich-- it was fun to see where we'd just been!