Jewish Holocaust fact
The Holocaust was the state-sponsored discrimination, harassment and eventual liquidation of European Jews by Nazi Germany and its Allies from 1933 to 1945. The Nazis termed this well-organized murderous policy as 'The Final Solution'. Aside from the over-flogged notion of biblical time crimes, there is no rational reason as to why the Nazis disliked the Jews to the extent they did. The Jews were neither a threat to the social and economic fabric of the German nation nor its political standing. But anti-Semitism was very much prevalent in Europe - and in America - way before the Nazis came into power, and the Jews became convenient and unfortunate scapegoats to pin the blame on for Germany's defeat in World War I, for the Great Depression, for the unemployment and poverty in Germany, for the rise of Communism, in fact, for anything and everything that was then going wrong socially and politically.

The Nazis also believed in half-baked racial theories that made them, as Aryans, superior to everyone else, especially the Jews, the Gypsies and the Slavs. These people were considered a threat to the biological purity of the Aryans and that was a good enough reason to relieve them of property and life. Other 'misfits' that were to be eliminated included homosexuals, Jehovah's Witnesses, Freemasons, physically and mentally handicapped people, communists and other political dissidents. Resources that could have been used for the war effort - soldiers, trains, supplies, etc - were diverted for the upkeep of the concentration camps set up for the destruction of the 'subhumans and misfits' and this hastened the end of Nazi Germany.

Let's look at some of the things that happened during the Holocaust:
Persecution of Jews and other 'Sub-Human' People:
The persecution of the Jews began in 1933. They had to wear yellow stars to mark them out from the rest of the populace and they were prohibited from participating in public life. They couldn't own businesses, ride on public transport, attend German schools and universities, rent apartments from Germans, marry non-Jews and so on. Public signs were put up saying 'Jews Not Allowed'. Life grew increasingly difficult and a few Jews managed to get out of Europe while it was still possible; for most of those that remained, death was the only way out. Out of the nine million Jews from 21 European countries, close to 6 million were killed in the Holocaust. In the 1930s, the Nazis began to euthanize mentally and physically-disabled Germans and Austrians. Over 5000 children were killed with lethal injections. Their parents had no say in the matter - they had to acquiesce or get arrested and thrown into prison.
Establishment of the Concentration Camps:
The Nazis established 39 concentration camps in total. The original intention of such camps was for holding political dissidents, but later ones were built to accommodate transports of Jews from the conquered Western European and Eastern European countries. Those that were not gassed on arrival - infants, young children, old people and the infirm were all usually gassed - had to face hard labor, starvation, exposure, brutality and disease. The Nazis established six extermination centers in Poland, where a long-established tradition of anti-Semitism made it easier to bring about the destruction of 90% of the Polish Jews. The most notorious death camps in Poland were Treblinka, Auschwitz and Sobibor; nearly 1.5 million Jews died in Auschwitz alone. Some other camps in Europe, where Jews were murdered, were Chelmno, Belzec, Majdanek, Mauthausen, Belsen, Buchenwald and Dachau.

After the Nazis invaded the Soviet Union in June 1941, Jews in those territories were rounded up and killed in gas vans. Jews were also marched to wooded ravines in the outskirts of villages and towns, forced to dig ditches and then made to undress before being shot in batches, falling into the open grave on top of one another. Very few managed to survive and escape when darkness fell. The camps were also notorious for using inmates as human guinea pigs to carry on horrific medical experiments, including high altitude tests, sterilization and castration. Children, especially twins, were experimented on by the 'Angel of Death', Dr. Josef Mengele. The reason the Nazis could transport so many Jews to the camps with relative ease was that very few of these people had any idea of what lay ahead, they had no arms with which to resist their heavily armed guards, and they got little assistance from the local populations. All Jews, however, did not go to the camps without resistance. Many fled to forests and organized partisan groups. There was resistance in the ghettos, notably in the Warsaw Ghetto, where the 'sub-humans' (as the Germans called the Jewish fighters), armed only with basic guns and home-made grenades held out against the well-equipped German army for several weeks.
Savior, Collaborators and the Allies:
Many individuals and groups in Germany as well as the Occupied Countries did everything they could, at considerable personal risk, to help save the Jews and other targeted people from the Nazis. The number of collaborators, unfortunately, was higher. Denmark and Bulgaria stand out as the only two European countries that went out of their way to save their Jews. Denmark saved 99% of their people by transporting 7800 Danish Jews over to neutral Sweden. In Bulgaria, the King and the government prevaricated about handing over the Jews and thus saved them.

By 1942, the Allies knew of the 'Final Solution' and the exact plan to murder Europe's Jewish population, including the existence of the concentration camps -

From intercepted German police and SS reports and dispatches.
From an intercepted memo by the Chilean Diplomat, Gonzalo Montt Rivas, informing his superiors about a German decree that revoked the citizenship of German Jews who lived abroad or had escaped abroad and seized their property and money. According to Rivas, this decree would richen the Reich and help 'solve' the problem of Jews in Europe. Written in Spanish, the English translation of this memo was in Allied hands by 20 March 1942.
From eyewitness accounts from escaped Jews and by members of the Jewish and Polish underground; particularly, in May 1942, from reports by the Jewish Socialist Bund party in the Warsaw Ghetto.
From a detailed report presented by the Polish courier Jan Karski. He traveled to London in November 1942, and met with the chairman of the Joint Intelligence Committee, William Cavendish-Bentinck, and informed him about the mass murder of Jews in the Warsaw Ghetto and the Belzec concentration camp.
Report by Jan Nowak-Jezioranski, in December 1943, about the liquidation of the Warsaw Ghetto.
From successfully breaking Germany's Enigma code and decoding German messages. They knew, for example, about the deportation of Italian Jews to Auschwitz in October 1943.
However, the Allies:
Chose to disbelieve the reports of German atrocities. As mentioned, the British already had access to intercepted German documents, but Cavendish-Bentinck, his Foreign Office colleague Roger Allen and Anthony Eden still refused to believe the Karski report. Roger Allen infamously wondered why the Germans would gas the Jews when it would be more convenient to machine gun or starve them, and Eden, in refusing Karski a meeting with Churchill, thought he ought to "protect the elderly and overworked Prime Minister from too many petitioners." This is one theory - that the War Cabinet and Churchill were not informed and therefore no action could be taken.
Were sufficiently anti-Semitic themselves to refuse to open their borders for Jewish refugees.
Were more interested in defeating the German military than saving Jewish lives. If they had bombed the railway tracks to Auschwitz, for example, many lives would have been saved; but it was not a 'military target'.
The Perpetrators:
What is additionally horrifying about the Final Solution is that the people who carried it were not all monsters and psychopaths and perverts and sadists - most were 'normal', ordinary people with perhaps more than an ordinary enthusiasm for National Socialism. They were capable of working the camps during the day and then spending the evenings in cultural and family-oriented pursuits. Later on, most tried to wriggle out of what they had done with the convenient excuse that they had only been following orders, they had only done what their superiors had asked them to do, that they personally couldn't be held responsible for those orders.

This excuse was thrown out at the Nuremberg War Trials - according to the Nuremberg judgment, even if you were a soldier, if you were ordered to do something horrific, it was your duty as a conscientious human being to refuse to do it. In accordance with this judgment, many of the Nazis were hanged for their crimes.

The Holocaust stands out for its frightening rationality and efficiency in systematically killing people, but, when you hear about events in Rwanda, Iraq and Afghanistan, it seems nothing has been learned about respecting human rights and human lives.