Pawiak Prison Museum

Museum in Warsaw

Dating from the 19th century, this former prison was built to incarcerate enemies of the Russian tsar. During WWII it was used by the Gestapo to imprison and torture mostly Polish political prisoners. It’s estimated that around 100,000 prisoners passed through these sinister gates from 1939 to 1944, of whom around 37,000 were executed. The prison was blown up by the Germans in 1944, but half of the mangled gateway, complete with rusting, barbed wire, and three detention cells (which you can visit) survive.