Awesome cafes, you explored only a tiny bit of what Krakow can suggest, I guess?
St.Petersburg also has such a coffee shop in an ancient tram wagon, but it does not look so fascinating (but have an option to sit at the wagon's roof! I have to shoot its inside design and then will be ready to share here...)
My sincere congratulations to @mipiano and @phortun, who were the better solvers of your travel riddles! This time it was even more harder nut to crack.