Warsaw Uprising Museum

Warsaw was devastated during World War II, and this museum details the horrors in terrible detail. A 3D video at the museum shows the city, flattened, after 1945 and notes that over 400,000 citizens were killed during the bombings.

It's a worthwhile, if depressing, visit -- in order to understand what the city, and the country, went through, and how it has shaped the current emotional and physical cityscape.