While the Second World War was still underway, the Nazis had already formed a contingency plan that if defeat was imminent they would carry out the total destruction of German records. Historians have documented evidence that as Germany's defeat became imminent and Nazi leaders realized they would most likely be captured and brought to trial, great effort was made to destroy all evidence of mass extermination.
Heinrich Himmler instructed his camp commandants to destroy records, crematoria (where bodies were burned), and other signs of mass extermination. As one of many examples, the bodies of the 25,000 mostly Latvian Jews whom Friedrich Jeckeln and the soldiers under his command had shot at Rumbula (near Riga) in late 1941 were dug up and burned in 1943. Similar operations were undertaken at Belzec, Treblinka and other death camps.
The Allied forces were still able to collect tremendous evidence of Nazi genocide. They took photographs of the death camps and collected documents from Nazi officials to be used as evidence. Then they put Nazi leaders on trial in Nuremberg, Germany.
The Nuremberg trials were televised, so the whole world could see the evidence of Nazi crimes against humanity.
Above, Rudolf Hess, a head Nazi official, is forced to sit for his trial.
A birds eye view of the trials.