This is the most comprehensive children's museums that we have visited. We had initially given this a half day, by did not see all so came back for a second visit, as ten year old enjoyed it so much. There are 4floors of activities in the Haus der Natur and another three floors in the adjoining science centre. There is a dinosaur exhibit, a beautiful aquarium. A hugely comprehensive geology section (which our ten year old loved), a space section which is partially interactive, an interactive Doppler section, a section about European animals, an older section about African animals, a section on the Salzach River, a reptile zoo with a large snake collection, a human body section showing everything from heart surgery performance to sexuallity and human reproduction. The latter section is not subtle, but it is possible to skip the room if your children are not ready for it. The Science Centre is fully interactive and allows children to explore everything from energy usage and climate change to the science of music to the challenges faced by wheelchair users, to operating a hydrolic lift. There was a very enjoyable live physics demonstration on when we visited. It was about a half an hour and involved the use of dry ice which my son enjoyed despite his not understanding much German. There is a nice restaurant and a gift shop too. The older exhibits had only German explanations but the newer and more interactive stuff was multilingual. Well worth a whole day visit with children. Very reasonable family entry fee and free entry with Salzburg Card.