The reconstructed crematorium (Krema I) and the trolley-switching mechanisms of Auschwitz I.

These crematorium ovens in the main Auschwitz camp was active from September, 1940 to July, 1943. There were a total of three ovens in operation. Thousands of bodies were incinerated in these ovens. The trolley on wheels were used to shove the bodies inside the crematorium. The current ovens were reconstructed in 1947 by Russians, when the camp was turned into museum.