I booked four days in Prague after hearing many friends rave about how wonderful of a city it was. Things like the Astronomical Clock and Charles bridge were wonderful to see, however the city is very much geared towards tourism, and the "must see" spots are exceptionally busy. The Lennon wall was closed for repairs, so I can't say much about it other than it was super easy to find with Google Maps. I think if I could go back, I would have dropped a day or two off my stay here to reallocate somewhere else.
A local laundromat was required by this point in my trip, and I found one that provided drinks and free wifi for you to enjoy while you waited in their waiting area full of chairs and couches.
I got to catch a concert in the Liechtenstein Palace where a quartet played a mix of old and new music. It was a lot of fun, and very entertaining. There are signs for it all over Prague, and I'm glad I was able to get a ticket. The Film Special Effects Museum is a really fun look into the history of special effects. It is more geared towards children, but if you are interested in that kind of thing, it's well worth spending an hour or so going through it. My last day I went to the Muzeum at the top of Wenceslas Square. It was a huge museum and is well worth the entrance fee.
Did you try the famous paella? Spain is just beautiful