Auschwitz-Birkenau played a central role in the Nazi's systematic extermination of the Jews of Europe. During the summer and autumn of 1941, Zyklon B gas was introduced into German concentration camps as a highly efficient means for murder. The SS initially converted two farmhouses for use as gas chambers, but judged these facilities inadequate for the scale of gassing they planned at Auschwitz-Birkenau. Four large crematorium buildings were constructed between March and June 1943. Each had three components: a disrobing area, a large gas chamber, and crematorium ovens. To prevent panic, the Nazis told new arrivals that they would be taking a shower. Instead they were gassed to death and then burnt in the crematoria. The SS continued gassing operations at Auschwitz-Birkenau until November 1944.