According to legend, Prague was virtually left untouched during WWII because Hitler wanted to retire there. Although there doesn’t seem to be any evidence of this, Prague’s beauty still doesn’t cease to amaze people, especially after learning about its German occupation. For a country that was caught in the middle of the war, its destruction is quite minimal compared to those surrounding it.
Even though the destruction it experienced during WWII was minimal, there definitely are reminders of that dark time. In Prague, probably the most obvious of this is the Old Town Hall on Staroměstské náměstí (Old Town Square). While the Astronomical Clock (which belongs to the oldest part of the building) remains intact, when looking at the opposite side facing Týn church, you can see a small park where the eastern wing of the town hall once stood.
This part was destroyed on May 8th, 1945 during the Prague uprising.
Inside you can find a tourist information center. You can also do a tour of the underground, which is pretty neat. The Old Town used to be much lower than it is today, but because of the constant flooding by the Vltava river, the city was elevated by trash and other materials in the 13th century. The remnants of that old buried part of Prague can be seen on the tour. If you're interested in going, here are a couple companies that go down there.