Throughout the years of World War II, the Mauthausen and its subcamps received new prisoners in smaller transports daily, mostly from other concentration camps in German-occupied Europe. Most of the prisoners at the subcamps of Mauthausen had been kept in a number of different detention sites before they arrived. The most notable of such centres for Mauthausen and its subcamps were the camps at Dachau and Auschwitz. The first transports from Auschwitz arrived in February 1942. The second transport in June of that year was much larger and numbered some 1,200 prisoners. Similar groups were sent from Auschwitz to Gusen and Mauthausen in April and November 1943, and then in January and February 1944. Finally, after Adolf Eichmann visited Mauthausen in May of that year, Mauthausen received the first group of roughly 8,000 Hungarian Jews from Auschwitz; the first group to be evacuated from that camp before the Soviet advance. Initially, the groups evacuated from Auschwitz consisted of qualified workers for the ever-growing industry of Mauthausen and its subcamps, but as the evacuation proceeded other categories of people were also transported to Mauthausen, Gusen, Vienna or Melk.