I came here last month having seen it on google maps whilst searching for things to do close to my hotel. There are guided tours every hour. There was a tour half an hour after I arrived, so I purchased a ticket (they take card payments, but I’m not sure if they take cash) and sat down and waited for the tour commence (there were seats you could sit on while you waited). The tour lasts an hour, and begins with a short video presentation on the history of the hospital and the background, which was very useful as I didn’t know much about the history of Hungary when it comes to conflicts. It can get a bit cool underground, as you go deeper into the rocks, so a light jacket or fleece or something is recommended, even on a hot day like the day I visited. If you don’t have one, they offer you a coat/cloak that would have been worn by staff at the hospital when it was active. The guided tour lasts an hour. The guide was very informative, and I found the tour very interesting. Scenes were set up using dummies so that we could see how the hospital would have looked when it was operational. There were a lot of tools that were used when the hospital was operational available to view in cabinets and drawers too. Definitely worth a visit if you have an hour to spare. Very close to the Mercure Castle Hill hotel (through the park opposite the hotel, and up the steps).