they were registered and not sent straight to the gas chamber, was at the prisoner reception center near the gate with the Arbeit macht frei sign, where they were tattooed, shaved, disinfected, and given a striped prison uniform. Built between 1942 and 1944, the center contained a bathhouse, laundry, and 19 gas chambers for delousing clothes. The prisoner reception center of Auschwitz I became the visitor reception center of the Auschwitz-Birkenau State Museum. Crematorium I, first gassings Construction of crematorium I began at Auschwitz I at the end of June or beginning of July 1940. Initially intended not for mass murder but for prisoners who had been executed or had otherwise died in the camp, the crematorium was in operation from August 1940 until July 1943, by which time the crematoria at Auschwitz II had taken over. By May 1942 three ovens had been installed in crematorium I, which together could burn 340 bodies in 24 hours. The first experimental gassing took place around August 1941, when Lagerführer Karl Fritzsch, at the instruction of Rudolf Höss, murdered a group of Soviet prisoners of war by throwing Zyklon B crystals into their basement cell in block 11 of Auschwitz I. A second group of 600 Soviet prisoners of war and around 250 sick Polish prisoners were gassed on 3–5 September. The morgue was later converted to a gas chamber able to hold at least 700–800 people. Zyklon B was dropped into the room through slits in the ceiling. First mass transport of Jews Historians have disagreed about the date the all-Jewish transports began arriving in Auschwitz. At the Wannsee Conference in Berlin on 20 January 1942, the Nazi leadership outlined, in euphemistic language, its plans for the Final Solution. According to Franciszek Piper, the Auschwitz commandant Rudolf Höss offered inconsistent accounts after the war, suggesting the extermination began in December 1941, January 1942, or before the establishment of the women's camp in March 1942. In Kommandant in Auschwitz, he wrote: "In the spring of 1942 the first transports of Jews, all earmarked for extermination, arrived from Upper Silesia." On 15 February 1942, according to Danuta Czech, a transport of Jews from Beuthen, Upper Silesia (Bytom, Poland), arrived at Auschwitz I and was sent straight to the gas chamber. In 1998 an eyewitness said the train contained "the women of Beuthen". Saul Friedländer wrote that the Beuthen Jews were from the Organization