Twins were subjected to weekly examinations and measurements of their physical attributes by Mengele or one of his assistants.[49] The experiments he performed on twins included unnecessary amputation of limbs, intentionally infecting one twin with typhus or some other disease, and transfusing the blood of one twin into the other. Many of the victims died while undergoing these procedures,[50] and those who survived the experiments were sometimes killed and their bodies dissected once Mengele had no further use for them.[51] Nyiszli recalled one occasion on which Mengele personally killed fourteen twins in one night by injecting their hearts with chloroform.[31] If one twin died from disease, he would kill the other twin to allow comparative post-mortem reports to be produced for research purposes.[52]
Upon arrival at a camp in mates were stripped of their clothes and shaved of all their body hair. Then they were given a shower, disinfected and given a uniform. each step was used to dehumanize prisoners, both physically and emotionally. Prisoners were then given a number. At Auschwitz the number was tattooed on their arm. Those who the Nazis thought were unable to work were token to what they called showers. The Nazis said to these prisoners who were about to meet their deaths it was to freshen up a bit after their long journey. Instead of water Zyklon B, developed to kill rodents, closed in on them. Death Did not usually come quickly but rather slowly. Most of the walls of the death chambers had scratch marks to show how victims tried to dig themselves out. The purpose of these cams were to kill huge amounts of Jews a day. Camps had been in Germany for years. These were the places  were tons of Jews had been murdered. Once at the camps selected people would work the others were gassed. Before being gassed they forced to march to the sound of music. An important camp was Treblinka. It was established for slave labor In 1941, but in 1942 it became a death camp. By may 1943 the population of Warsaw had been transported to Treblinka and other camps. By July 11, 1944 800,000 Jews had been murdered in Treblinkia. Unlike Treblinkia, Chelmno, Sobibor, and Balzac which were made to kill Jews. Maidanek and Auschwitz had a work camp attached. Upon arrival at these two camps a selection was made. 10% of the new arrivals would escape immediate gassing.   
The Nazis, under cover of the war, developed the technology, bureaucracy, and psychology of hate to efficiently murder millions of Jews. The details of the “Final Solution” were worked out at the Wannsee Conference. All Jews in Germany and the occupied countries were deported to sealed ghettos as a holding area. Many were then shipped in cattle cars to labor camps where they lived under brutally inhuman conditions. Hundreds of thousands were sent directly to the gas chambers in death camps. As the Allies advanced on the camps, death marches further depleted the ranks of potential camp survivors.
One day this past fall I walked the grounds of the Ponar forest with Freund­ and a couple of his colleagues, who had recently completed a surveying project of the area. Snow had been forecast, but by late morning the only precipitation was icy rain, driven sideways by the wind. The forest was mostly empty, save for a group of ten Israelis who had arrived that morning; they all had family from Vilnius, one of the men explained, and were honoring them by visiting local Holocaust sites.
Mengele was born on 16 March 1911 to Walburga (née Hupfauer) and Karl Mengele in Günzburg, Bavaria, Germany.[4] He was the oldest of three children; his two younger brothers were Karl Jr. and Alois. Their father was founder of the Karl Mengele & Sons company, producers of farm machinery.[5] Josef was successful at school and developed an interest in music, art, and skiing.[6] He completed high school in April 1930 and went on to study philosophy in Munich,[7] where the headquarters of the Nazi Party were located.[8] In 1931, Mengele joined the Stahlhelm, Bund der Frontsoldaten, a paramilitary organization that was absorbed into the Nazi Sturmabteilung (Storm Detachment; SA) in 1934.[7][9]