A single visit will not be enough to do justice to what is on offer. Unless you are an expert, say in Mineralogy, an audio guide is a must. You can get an English language audio guide which offers an excellent commentary accessible for all ages. It will highlight the Top 100 exhibits for which you should be prepared to allot several hours. I somehow missed some of the numbers which were sometimes like a scavenger hunt to locate. Whether it is the meteorite hall or the dinosaur exhibit, you will learn something new and come away totally satisfied with the experience. The quality and range of the specimens is amazing and unlikely to be seen in many places elsewhere in the world, at least under a single roof. I would rate this amongst the top 10 places to visit in Vienna and it was not even on my radar before coming here.