Extermination camp Extermination camps ( or death camps ) were camps during World War II ( 1939 – 45 ) built primarily but not exclusively by Nazi Germany to systematically kill millions of people by execution ( primarily by gassing ) and extreme work under starvation conditions . While there were victims from many groups , Jews were the main Nazi targets . This genocide of the Jewish people was the Third Reich ' s " Final Solution to the Jewish question " . The Nazi attempts at Jewish genocide are collectively known as the Holocaust . While not on the same scale as that prosecuted by the Nazis , the fascist Ustaše forces of the Independent State of Croatia operated an extermination camp policy . Background . The Nazis used the euphemism " Endlösung der Judenfrage " ( Final Solution of the Jewish Question ) to describe their systematic killing of Europe ' s Jews , which Nazi leaders likely decided during the first half of 1941 . The initial , formal killings of the Final Solution were undertaken by the SS " Einsatzgruppen " ( Task Forces ) death squads who followed the Wehrmacht during the " Operation Barbarossa " invasion of the USSR in June 1941 . The initial extermination method of shooting people in burial pits proved logistically and psychologically inefficient . After the war , the diary of the Auschwitz Commandant , Rudolf Höss , revealed that psychologically " unable to endure wading through blood any longer " , many " Einsatzkommando s " – the killers – either went mad or killed themselves . Thus in late 1941 , the Nazis established camps specifically for mass extermination via gas chambers . The logistical details were established in the Wannsee Conference ( January 1942 ) and were executed by the administrator Adolf Eichmann . In 1942 , the " Reichsführer " Heinrich Himmler ordered the Lublin District " SS - und Polizeiführer " Odilo Globocnik to build the first extermination camps during " The Final Solution " ( 1941 – 43 ) , the operation to annihilate every Jew in the General Government ( occupied Poland ) . Initially , the victims ' corpses were buried in mass graves , but later were cremated . After Russian forces began to advance , previously buried victims were also exhumed and burned in Sonderaktion 1005 , a Nazi attempt to destroy evidence of the Holocaust . The first concentration [ extermination ? ] camps were under the direct command of SS – Polizei - führer Globocnik , and operated by SS Police battalions and Trawnikis – volunteers from Eastern Europe ; whereas the " SS - Totenkopfverbände " managed the Nazi concentration camps such as Dachau and Ravensbrück . The Nazis did not expect the majority of prisoners taken to the Belzec , Treblinka , and Sobibor extermination camps to survive more than a few hours beyond arrival . Definitions . The terms " extermination camp " ( " Vernichtungslager " ) and " death camp " ( " Todeslager " ) are interchangeable usages , each referring to camps whose primary function was genocide , not for punishing crime or containing political prisoners , but for the systematic killing of the prisoners delivered there . Nazi Germany ( 1933 – 45 ) built the most infamous extermination camps in Occupied Poland . These differed from concentration camps , such as Dachau and Belsen , which were initially prison camps for people defined as socially or politically undesirable in Nazi society . In the early years of the Holocaust , the Jews were primarily sent to concentration camps , but from 1942 onwards they were mostly deported to the extermination camps . Extermination camps are distinguished from the " Arbeitslager " ( forced labor camp s ) established in German - occupied countries to use the prisoners , including prisoners of war , as slave labor . In most camps ( excepting PoW camps for the non - Soviet soldiers and certain labor camps ) , the high death rates resulted from execution , starvation , disease , exhaustion , and physical brutality . The Nazis distinguished between extermination camps and concentration camps . As early as September 1942 , Dr . Johann Paul Kremer , M . D . , an SS physician , witnessed a gassing of prisoners , and in his diary wrote : " They don ' t call Auschwitz the camp of annihilation [ " das Lager der Vernichtung " ] for nothing ! " The distinction was evident during the Nuremberg trials , when Dieter Wisliceny ( a deputy to Adolf Eichmann ) was asked to name the " extermination " camps , and he identified Auschwitz and Majdanek as such . Then , when asked " How do you classify the camps Mauthausen , Dachau , and Buchenwald ? " he replied , " They were normal concentration camps , from the point of view of the department of Eichmann . " The camps . For political and logistical reasons , the extermination camps were built primarily but not exclusively by Nazi Germany in occupied Poland . The Polish death factories were established where most of the intended victims lived ; Poland had the greatest European Jewish populace . On top of that , the camps outside of the Third Reich proper could be kept secret from the German civil populace . Operationally , there were two types of death camp . Pure extermination camps . Gas van s producing poisonous Carbon monoxide exhaust fumes were initially developed at the Chelmno extermination camp , before being used elsewhere . The camps at Treblinka , Bełżec , and Sobibor were constructed during Operation Reinhard ( October 1941 – November 1943 ) , for the extermination of Poland ' s Jews . Prisoners were promptly killed upon arrival . Initially , the camps used carbon monoxide gas chambers ; at first , the corpses were buried , but then incinerated atop pyres . Later , gas chambers and crematoria were built in Treblinka and Belzec ; Zyklon - B was used in Belzec . Whereas the Auschwitz II ( Auschwitz – Birkenau ) and Majdanek camps were parts of a labor camp complex , the Operation Reinhard camps and the Chełmno camp were exclusively for the quick extermination of many people ( primarily Jews ) within hours of their arrival . Some able - bodied prisoners delivered to the death camp were not immediately killed , but were forced into labor units ( " Sonderkommando " ) to work at the extermination process , removing corpses from the gas chambers and burning them . Because the extermination camps were physically small ( only several hundred metres long and wide ) and equipped with minimal housing and support installations , the Nazis deceived the prisoners upon their arrival , telling them that they were at a temporary transit stop , and soon would continue to an " Arbeitslager " ( work camp ) farther east . Concentration – extermination camps . Some prisoners were selected for slave labor , instead of immediate death ; they were kept alive as camp inmates , available to work wherever the rulers required . Three extermination camps – Auschwitz , Majdanek , and the Ustaše run Jasenovac – were later retrofitted with Zyklon - B gas chambers and crematoria , remaining operational until war ' s end in 1945 . Jasenovac concentration camp was a complex of sub - camps in Yugoslavia and was the only extermination camp not operated by Nazis , but by the fascist Ustaše forces of the Independent State of Croatia , the majority of whose victims were Orthodox Christian Serbs , Roma , and Jews . Many inmates arriving at Jasenovac were scheduled for systematic extermination . An important criterion for selection was the duration of a prisoner ' s anticipated detention . Strong men capable of labor and sentenced to less than three years of incarceration were allowed to live . All inmates with indeterminate sentences or sentences of three years or more were immediately scheduled for execution , regardless of their fitness . Some of the mass executions were mechanical following Nazi methodology . Others were performed manually utilising tools such as mallets and agricultural knives . Maly Trostenets extermination camp in the USSR initially operated as a prison camp . It became an extermination camp later in the war with victims initially under going mass shootings . This was supplemented with exhaust fume gassing in a van from October 1943 . Sajmište concentration camp operated by the Nazis in Yugoslavia had a gas van stationed for use from March to June 1942 . Once the industrial killings were completed , the van was returned to Berlin . After a refit the van was then sent to Maly Trostinets for use at the camp there . Janowska concentration camp near Lwow in Poland operated a selection process for the detainees . Some prisoners were assigned to work . Others were either transported to Belzec or victims of mass shootings on two slopes in the Piaski sand - hills behind the camp . The Warsaw concentration camp was an associated group of the German Nazi concentration camps , possibly including an extermination camp , located in German - occupied Warsaw . The various details regarding the camp are very controversial and remain subject of historical research and public debate . Numbers of victims . Nazi . The estimated total number of people killed in the Nazi camps in the table below is over three million : At the Maly Trostenets extermination camp in Belarus , USSR , some 65 , 000 Jews were killed , whilst the estimated number of gentile s ( non - Jews , i . e . communists , priests , non - religious , soldiers , etc . ) varies between 100 , 000 to 400 , 000 . Ustaše . For a number of reasons such as lack of records and political bias , estimates vary from 100 , 000 to 700 , 000 in Croatia at Jasenovac ( August 1941 – April 1945 ) . Systematic mass killing . Nazi . Gassing . Each extermination camp operated differently , yet each had designs for quick and efficient industrialized killing . The formal industrial mass - killing method at the extermination camps was initially poisonous Carbon monoxide exhaust fumes . At Auschwitz and Majdanek there was a later deployment of Zyklon - B poison gas ( made to order by the IG Farben chemicals company ) . Besides gassing , the camp guards continued killing prisoners via mass shooting , starvation , torture , etc . SS " Obersturmführer " Kurt Gerstein , of the Institute for Hygiene of the Waffen - SS , during the war told a Swedish diplomat of life in a death camp , of how , on 19 August 1942 , he arrived at Belzec extermination camp ( which was equipped with carbon monoxide gas chamber s ) and was shown the unloading of 45 train cars filled with 6 , 700 Jews , many already dead , but the rest were marched naked to the gas chambers , where : " Unterscharführer " Hackenholt was making great efforts to get the engine running . But it doesn ' t go . Captain Wirth comes up . I can see he is afraid , because I am present at a disaster . Yes , I see it all and I wait . My stopwatch showed it all , 50 minutes , 70 minutes , and the diesel [ engine ] did not start . The people wait inside the gas chambers . In vain . They can be heard weeping , " like in the synagogue " , says Professor Pfannenstiel , his eyes glued to a window in the wooden door . Furious , Captain Wirth lashes the Ukrainian [ prisoner ] assisting Hackenholt twelve , thirteen times , in the face . After 2 hours and 49 minutes – the stopwatch recorded it all – the diesel started . Up to that moment , the people shut up in those four crowded chambers were still alive , four times 750 persons , in four times 45 cubic meters . Another 25 minutes elapsed . Many were already dead , that could be seen through the small window , because an electric lamp inside lit up the chamber for a few moments . After 28 minutes , only a few were still alive . Finally , after 32 minutes , all were dead . . . Dentists [ then ] hammered out gold teeth , bridges , and crowns . In the midst of them stood Captain Wirth . He was in his element , and , showing me a large can full of teeth , he said : " See , for yourself , the weight of that gold ! It ' s only from yesterday , and the day before . You can ' t imagine what we find every day – dollars , diamonds , gold . You ' ll see for yourself ! " Auschwitz Camp Commandant Rudolf Höss reported that the first time Zyklon B gas was used on the Jews , many suspected they were to be killed – despite having been deceived into believing they were to be deloused and then returned to the camp . As a result , the Nazis identified and isolated " difficult individuals " who might alert the prisoners , and removed them from the mass – lest they incite revolt among the deceived majority of prisoners en route to the gas chambers . The " difficult " prisoners were led to a site out of view to be killed off discreetly . A prisoner " Sonderkommando " ( Special Detachment ) effected the most of the " processes " of extermination ; they accompanied the Jews into the gas chamber ( a chamber room , usually outfitted to appear as a large shower room , with ( nonworking ) water nozzles , tile walls , etc . ) and remained with them until just before the chamber door closed . To psychologically maintain the " calming effect " of the delousing deception , an SS guard stood at the door , as if awaiting the prisoners . The " Sonderkommando " hurried them to undress and enter the " shower room " as quickly as possible ; to that effect , they also assisted the aged and the very young in undressing . To further persuade the prisoners that nothing harmful was happening , the " Sonderkommando " deceived them with small talk about camp life . Fearing that the delousing " disinfectant " might harm their children , many mothers hid their infants beneath their piled clothes . Camp Commandant Höss reported that the " men of the Special Detachment were particularly on the look - out for this " , and encouraged the women to take their children into the " shower room " . Likewise , the " Sonderkommando " comforted older children who might cry " because of the strangeness of being undressed in this fashion " . Yet , not every prisoner was deceived by such psychological warfare tactics ; Commandant Höss reported of Jews " who either guessed , or knew , what awaited them , nevertheless . . . [ they ] found the courage to joke with the children , to encourage them , despite the mortal terror visible in their own eyes " . Some women would suddenly " give the most terrible shrieks while undressing , or tear their hair , or scream like maniacs " ; the " Sonderkommando " immediately took them away for execution by shooting . In such circumstances , others , meaning to save themselves at the gas chamber ' s threshold , betrayed the identities and " revealed the addresses of those members of their race still in hiding " . Once the door of the filled gas chamber was sealed , pellets of Zyklon B were dropped through special holes in the roof . Nazi regulations required that the Camp Commandant supervise the preparations , the gassing ( through a peephole ) , and the aftermath looting of the corpses . Commandant Höss reported that the gassed victims " showed no signs of convulsion " ; the Auschwitz camp physicians attributed that to the " paralyzing effect on the lungs " of the Zyklon - B gas , which killed " before " the victim began suffering convulsions . As a matter of political training , some high - ranked Nazi Party leaders and SS officers were sent to Auschwitz – Birkenau to witness the gassings ; Höss reported that " all were deeply impressed by what they saw . . . [ yet some ] . . . who had previously spoken most loudly , about the necessity for this extermination , fell silent once they had actually seen the ' final solution of the Jewish problem ' . " As the Auschwitz Camp Commandant Rudolf Höss justified the extermination by explaining the need for " the iron determination with which we must carry out Hitler ' s orders " ; yet saw that even " [ Adolf ] Eichmann , who certainly [ was ] tough enough , had no wish to change places with me . " Corpse disposal . After the gassings , the " Sonderkommando " removed the corpses from the gas chamber , then extracted any gold teeth , and – to minimize the distinct smell of burning human hair – they shaved the corpses , before delivering them to the crematoria or to the fire pits , thus maintaining secret the existence of the extermination camp . The " Sonderkommando " were responsible for burning the corpses , and stoking the fires , draining body fat , and turning over the " mountain of burning corpses " for even combustion and a peak fire - temperature . Commandant Höss was impressed by the diligence of the " Sonderkommando " prisoners , despite their being " well aware that . . . they , too , would meet exactly the same fate " , yet always doing their jobs " in such a matter - of - course manner that they might , themselves , have been the exterminators " . Höss further reported that the men ate and smoked " even when engaged in the grisly job of burning corpses " , in the course of which they occasionally encountered the corpse of a relative , but , although they " were obviously affected by this . . . it never led to any incident " of revolt , as in the case of a " Sonderkommando " who so encountered the corpse of his wife , yet behaved " as though nothing had happened " . The corpses were incinerated in crematoria and the ashes either buried or scattered ; yet , at Sobibor , Treblinka , Belzec , and Chelmno , the corpses were incinerated on pyres . The efficiency of industrialised killing at Auschwitz - Birkenau produced too many corpses to adequately burn or bury , so the crematoria ( manufactured to specification by Topf und Söhne ) were put into use to handle the disposals around the clock , day and night . Ustaše . The mechanical means of mass killing included following Nazi methods and the use initially of gas vans and later Zyklon B in stationery gas chambers . The Jasenovac guards have also been reported to have cremated living inmates in the crematorium . A notable difference of the Jasenovac guards compared to the SS at the Nazi camps was the widespread use of manual methods in the mass killings . These involved instruments such as mallets and agricultural knives . The post - war period . In 1944 , as the Red Army advanced into eastern Poland , the Nazis either partly or completely dismantled the eastern - most extermination camps to conceal the mass killings done there , and the buried remains ( excepting Auschwitz – Birkenau , which was partially demolished in 1947 ) . Because most of the death camps in the far east of the country ( Belzec and Sobibor ) had been constructed with local lumber , the physical installations were quickly deteriorated , eroded , and destroyed , by the natural elements . In the post - war period , the Communist government of the People ' s Republic of Poland ( 1944 – 90 ) created monuments at the extermination camp sites , that mentioned no ethnic , religious , or national particulars of the Nazi victims . The extermination camps sites have been accessible to Western visitors to Poland ; the camps are tourist attractions , especially the most - infamous Nazi death camp , Auschwitz concentration camp , near the town of Oświęcim ( Auschwitz ) . March of the Living is organized yearly since 1988 . In the early 1990s , Jewish Holocaust organisations disputed with Polish Catholic groups about : " What religious symbols of martyrdom are appropriate as memorials in a Nazi death camp such as Auschwitz ? " The Jews opposed to the erection of Christian memorials at a quarry adjacent to the Auschwitz camp , wherein featured the Auschwitz cross – a Roman cross erected near death camp Auschwitz I , where mostly Poles were killed , rather than at Auschwitz II ( Auschwitz - Birkenau ) , where mostly Jews were killed . Holocaust denial . Holocaust deniers are people and organisations who assert that the Holocaust did not occur , or that it did not occur in the historically recognized manner and extent . Holocaust denial goes beyond respected practices of historical revisionism to distort and deny history along preconceived notions , in what is called negationism . Extermination camp research is difficult because of extensive attempts by the SS and Nazi regime to conceal the existence of the extermination camps . As a result of Sonderaktion 1005 , camps were dismantled , records destroyed , and mass graves were dug up . Furthermore , extermination camps that remained uncleared were liberated by Soviet troops , who had different standards of documentation and openness than the Western allies . The existence of the extermination camps is firmly established by testimonies of camp survivors and Final Solution perpetrators , material evidence ( the remaining camps , etc . ) , Nazi photographs and films of the killings , and camp administration records . Holocaust deniers often start by pointing out legitimate public misconceptions about the extermination camps . For example , widely published images in America were mostly of typhoid victims and Soviet POWs at the Buchenwald and Dachau concentration camps – the first to be liberated by American troops and the most available imagery in America . In early news reports and for years afterwards these images were often used by the news media somewhat inaccurately in conjunction with descriptions of extermination camps and Jewish suffering . Holocaust deniers , after pointing out such common errors , put it forward as " evidence " extermination camps did not exist and the limited evidence about them is mostly a hoax arising out of a deliberate Jewish conspiracy . Holocaust denial is highly discredited by scholars and is a criminal offence in Austria , Belgium , France , Germany , Lithuania , the Netherlands , Poland , and Switzerland .