I definitely recommend the walking tour. It is free with the option to tip your guide at the conclusion. It takes about 2 hours total, and you see many of the main sights of Prague with a coffee break in between. It offers a wonderful history lesson so you understand more about what you are seeing. Jirka, our guide, was extremely knowledgeable and humorous at times, always keeping the attention of our group. He also was able to answer any questions and provide Prague recommendations for those that asked, for example, more local lunch spots for us. I think it's worth taking the tour on your first day, so you get an idea and then return to the sights you want to explore in greater detail. My only downside to the tour was standing so far from some of the sights, rather than walking to them and then listening to our guide, so you only saw things from a distance at times.
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