Very interesting modern museum on the Katyn massacre of ~22,000 people. The museum covers the Soviet massacre of primarily Polish military and police officers that was denied by the Soviets until 1990. Contains a vast array of the victim's possessions found during the excavations. Well worth a visit. If you do not speak Polish, you definitely need the audio guide as unfortunately almost nothing in the displays and multimedia is in English. The audio guide provides a broad description of the massacre, but does not delve in too much on the display items.