Chełmno extermination camp was built during WWII. The monument was built consisting of two rectangle-shaped blocks with some beautiful sculptures of victims on one and written pamiętamy (remember) on another.
As Adolf Eichmann was a major organizer of the Holocaust, he had to visit many exterminating zones, including the Chełmno extermination camp in Poland. Adolf Eichmann spectated a large-scale killing of Polish Jews.
Source: Wikipedia