I want to make some notes about biking in Prague. First of all, you should find a bike map. there are posted and marked bike routes and you should know where they are. Second, have your hotel on the castle side of the river, somewhat north of the castle. The ground there is flat and in the newer sections, there are less cobblestones. Third, have a bike with a lot of gears. three is not enough if you are towing a dog, for example. Fourth, the sidewalk's cobblestones are much smaller than the street's cobblestones and will make you feel less shaken to bits. Also, the traffic is scary and the sidewalk feels safer, even if slower. The natives seem to use the sidewalk. Also, the natives wear helmets, which is a sign that you should too. Sixth, watch out for doors. People do not look before jumping out of their cars and could easily smack you. Prague is definitely a 'bike to the edge of the section you want to see and then park your bike' kind of town.