I'm traveling throughout Europe this summer (Munich, Vienna, Budapest, Prague, Krakow, Dubrovnik, Amsterdam, Bruges, Dublin, etc.) and wondered what walking tours exist in these places that are like "London Walks." I'm not looking for a free tour in which the guide recites a canned script and then begs for tips at the end of the tour. I would love something that you don't have to prebook, you just show up at the alloted time, pay a reasonable amount and have a qualified guide.
So RS World -- which other tour operators are like London Walks in other cities of Europe? Thanks in advance.