The Holocaust refers to the massive killing or genocide of Jews during World War II by the Nazis and their allies. It is estimated that about five million Jews, including one million Jewish children, were murdered during the Holocaust. The total loss of life including the genocide of other ethnic and minority groups (the physically disabled, mentally challenged, communists, homosexuals, etc.) is put at around eleven million.
The Holocaust was a result of widespread feeling in Germany that some groups were more valuable than others and the term "final solution" (extermination) was coined to describe the ultimate solution to the "Jewish problem". Extermination camps were set up throughout Germany and its conquered territories. The most common methods employed included gas chambers and shootings. Many people escaped the Holocaust by escaping to other countries, with the most notable example being Albert Einstein.
The holocaust was a period of time starting in the 1930's where Nazi's were in power in Germany. They targeted groups of different races, gypsies, those who had disabilities, certain groups such as the Poles and Russians, homosexuals and others, the largest targeted being the Jewish population. The Nazis would murder these people in numerous ways. Some were sent to concentration camps where they would face death by disease, malnutrition, gas chambers, and even be experimented on. It was around the 1940's when concentration camps became the "go-to place" for the victims.
Nearing the end of the Holocaust when liberation was being reached for those persecuted, many of the victims were moved by train or on long death marches that would typically cause a lot of deaths. This allowed for a smaller amount of liberated individuals to survive.
On May 7, 1945 the Germans surrendered to the Allies and the death marches and concentration camps were closed. Any who were victims were officially liberated.