One thing I love about Europe is the abundance of free tours. In Prague, I just stumbled upon people with signs and colorful umbrellas in the old town square. In Polish cities, freewalkingtour.com is the major player. I went on their tours in Warsaw and Krakow, and in both cases I felt like I got a great overview of the city. The guides threw in a lot of Polish history and (perhaps apocryphal) anecdotes that kept me very entertained. I’d definitely recommend a tour as one of your first activities in town—then you can see what looks most interesting and return to it later.
The Krakow tour begins at St. Mary’s Church in the market square.
The (very large) square is laid out geometrically, except this church is at an awkward angle to the rest of the buildings. Our guide explained that even more important than the plan for the square was the rule that churches face east. Every hour on the hour, a trumpeter (a member of the fire department, in fact) appears in the top windows of the left-hand tower and plays a tune four times, in the four directions. The tune is awkwardly cut off—supposedly, many years ago the town trumpeter saw enemies approaching and played to warn the town. Unfortunately, the enemies heard him, and a well-placed arrow killed him before he could finish the tune. Now the tune is traditionally cut off mid-note in his memory.