Atlas Obscura is one of the largest, most well-known and most impeccably awesome archives of amazing places, foods and experiences in the world.
Here is their list of places to see in Austria! From the beautiful baroque library of the Hapsburg empire, to a macabre museum devoted to historical Viennese murders, to a spherical "micro-nation" right in the heart of Vienna, to a collection of handsomely-crafted representations of our round planet, Austria is a wonderful and charming country full of wonder at every turn! How many of these awesome spots have you been to?
Note: Some of these you cannot visit or see anymore, which have been marked with (Permanently Closed). So therefore, if you haven't already seen them, I don't know if you'll ever be able to completely finish this list.
Note 2: This is as of May 14, 2024. Sorry future people, there will definitely be more that can't be added.