Nogi drop in gyms around Europe?

I’m looking at travelling around Europe this summer and really would like to try dropping into some gyms to see what it’s like. I’ll be visiting the following cities: Prague, Munich, Vienna, Ljubljana, Split, Zagreb, and Athens. Does anyone have any suggestions for places I’ll be able to drop into for NoGi sessions? If you go to a gym in the area please let me know what your gyms like!