Besides searching for pianos, we also had time for some sightseeing. The castle was an obvious place to see, and hanging at the Vltava river is always fun. I also like the district of Žižkov a lot. It is an old working-class district which used to be independent, left-wing, bohemian, somewhat rough and proud about it.
There is also a cool looking TV-tower in Žižkov:
Following a hint by a friend we met, we found also one more piano. This one was in Myslbek shopping gallery, close to the old town.