We stopped by Burg Kaprun (Kaprun Castle) while in the Zell am See/Kaprun area. We didn't go inside, but walked around the grounds and checked out the exterior. It's a really cool old castle and makes for a nice quick stop and some great pictures!
There's also a beautiful little chapel, St. Jacob's Chapel (Jakobskapelle), right next to the castle that's worth walking over to see. We only saw the outside of the chapel as well, but it added to the charm of the area.
Definitely worth a quick stop if you're already nearby, even if you don't plan on touring the inside of the castle! read more