Chełmno extermination camp ([ˈxɛu̯mnɔ], approximately KHEHM-no; German: Vernichtungslager Kulmhof), built during World War II, was the first of the Nazi German extermination camps and was situated 50 kilometres (31 miles) north of the metropolitan city of Łódź (at the time renamed to Litzmannstadt), near the village of Chełmno nad Nerem (German: Kulmhof an der Nehr). Following the invasion of Poland in 1939, Germany annexed the area into the new territory of Reichsgau Wartheland, aiming at its complete "Germanization"; the camp was set up specifically to carry out ethnic cleansing through mass killings.