Isobars are atoms that have same atomic mass but different atomic number. They have different atomic numbers because they have different numbers of protons. They have the same atomic mass because they have just enough neutrons to make the same total of nucleons. Isobars occur at different places in the Periodic Table.
The Holocaust (also called Ha-Shoah in Hebrew) refers to the period from January 30, 1933 - when Adolf Hitler became chancellor of Germany - to May 8, 1945, when the war in Europe officially ended.
The Holocaust lasted for 12 years, until 1945. Starting as early as 1944, the Allies were advancing on the Germans finally and they began taking over their camps. In July 1944, Maidanek, a camp in Poland, was liberated by the Soviets. This was followed by many more liberations and takeovers as the Americans and other Allies slowly removed Hitler from power. In January 1945, Auschwitz was liberated.