The tower called Narrenturm was built in 1784 and back then it was the first psychiatric hospital in the world. The rotunda offered solitary cells for 139 inmates. The Narrenturm is part of the area that had once been the general hospital of Vienna, since 1998 it’s the campus of the main university.
Nowadays the tower is home to Vienna’s Pathologic-anatomical Museum. One can have a look at human and animal exhibits, a lot of diseases (should get some people to start wearing condoms each and every time!) and malformations, but also medical devices that make you wonder on what planet they might have been in use. In 2010 the Narrenturm counted over 20,000 visitors.
Just across the street, a tip on where to have lunch: Pie Factory.
This museum is definitely something one doesn’t get the chance to see in every city! No excuse for those on small budgets because the entry is only €2. The only drawback one could find are the very limited opening hours, but this way the visit is just more of an exclusive one.
About once a month they offer guided night tours at € 10, for these you need to register! Find all their events here, search for “NHM Narrenturm” in the category, results are most extensive in the German version ;).