The Holocaust ended at the end of WWII. The Nazi were defeated due to being defeated in war. They were defeated by Russia and the US who were called the allies. The holocaust ended in certain places when the allies let go of the prisoners in the camps in 1944-1945. After Hitler died , in 1945 the Germans decided surrendered and let go of all Jewish prisoners. The allied armies all came into Germany to let go 

of the concentration camps & people. 

Hitler killed himself on 30th April 1945, and the war in Europe ended on 8th May. What happened to his body is shrouded in mystery. One of his staff burned the bodies of Hitler and his wife and dog in a bomb crater outside the Reich Chancellery, the bunker of which was where Hitler spent his final days and where he died. The Russian secret service found the charred remains and claimed to have buried them, then dug them up again in 1970 and cremated them.