I will take this opportunity to bore the XPT community with a few of my own Prague picks ...
Charles Bridge is always crowded.
The Hebrew around Jesus is from Isaiah and means "Holy, Holy, Holy." It is a verse that is chanted in every synagogue every day as part of the Kedushah ... Kadosh! Kadosh! Kadosh! Adonai tz'vaot m'lo khol ha'aretz k'vodo!
I'm fasinated by the digits 4 and 7 on the Astronomical Clock.
All those winding narrow streets suddenly open to a boulevard!
And, a rather beautiful and interesting street it is! Up at the end/top is that museum.