While near Salzburg, make sure that you don't miss the salt mines that are available for tours here! We went with the one in Hallein since it matched our itinerary, however there is one in Berchtesgaden if that is preferable. Based on our experience, I would say that it is a fun activity and you should definitely check it out for both the slides, the train, and the history.
There are plenty of things to see and do here which maps the trip worthwhile. Included when we went in 2015 were 2 slides, a showcase of the oldest wooden staircase in Europe, a mine train that takes you out of the mine, and a small museum. In all, it took us about 1.5 hours from start to finish of the tour of the salt mine. After the tour, you are free to wander the grounds and for the look-out point that is not to be missed.
When you go, I would suggest that you avoid heels and nicer clothes. When you arrive, you are fitted in a jump suit that is included in the tour to keep you from getting dirty, however, they don't provide full protection and since the ground may be muddy, wearing some shoes that you don't mind getting dirty is probably a good idea.
Fun fact, 'salz' is actually 'salt' in German and in the past, salt was an important commodity, so important that cities where named after it, examples being Salzburg and Salzkammergut.
For more information, visit the official website at https://www.salzwelten.at/en/home/
Come back next Friday for another Past Point of Interest!