This is at the back door of the Castle Museum. There was a castle here and you can see a great exhibitiion about it.
The Museum of Szeged is also there with the new fountain.
(This cache has two more secret functions. It is the final stage of a multi cache played on geocaching.hu: GCszev: https://geocaching.hu/caches.geo?id=2487 and it is the reward for the completion of an Adventure Lab: Vár ami volt - Szeged Fortress.)
Enjoy :)