Big second to Szeczenyi baths in Budapest.
Awesome, and cheap, cheap, cheap.
Since we did the overnight train from Munich and our hostel beds weren’t ready to check into when we arrived, so we chilled out there for the afternoon. Very relaxing.
We did the synagogues in Prague (including the one with the names on the wall) and the big synagogue in Budapest- worth seeing.
The Kunst (art) museum in Vienna is amazing.
For the love of the deity of your choice, stay away from Czech absinthe and the Zwack Unicum. Only bad things can happen.