TerezĂn, or Theresienstadt, as the Germans called it, was unique in that it did not fit the definition of a concentration camp or a ghetto; it was used both as a way-station for those being sent to other camps farther east and as a place to house specific populations of Jews, including decorated veterans of World War I, the elderly, and prominent individuals whose disappearance might be widely reported or who would be unfit for forced labor. The inmates included a number of famous poets, painters, musicians, composers, and scholars. Partly for this reason, TerezĂn had an unusual number of cultural activities for adults and children; some artwork and music created there survived the war.
In 1944, in response to pressure from Denmark after the deportation of Danish Jews to TerezĂn, the Nazis invited the Danish Red Cross, the Danish foreign minister, and the International Red Cross to inspect the camp. Before the visitors arrived, prisoners were ordered to pave streets, repair housing, build a playground, and even plant 1,200 rosebushes. The Nazis also deported 7,500 young men and women to Auschwitz to make the camp less crowded and to substantiate their claim that it was a ghetto for old people. In this way, TerezĂn became a propaganda tool to hide what was really happening to the Jews.
https://www.facinghistory.org/resource-library/terezin-site-deception
As the government and military began to collapse within Germany, Nazi officials in both Germany and occupied Poland began to think about their endgame. In November 1944, Heinrich Himmler, head of the SS and one of the architects of the Holocaust, issued an abrupt order to destroy the gas chambers at Auschwitz-Birkenau, the largest of Auschwitz’s three main camps. Historians disagree on why he issued the command, which was in direct opposition to a previous order by Adolf Hitler to destroy the remaining Jews in Europe.
Officials at the camp obeyed Himmler. In late 1944, they dismantled part of the gas chambers, forcing, eyewitnesses would later recall, the Sonderkommando—a group of mostly Jewish prisoners who were made to run the gas chambers—to dismantle the structures piece by piece. Then, as the Russians closed in that January, the remaining buildings were destroyed, blown up completely using dynamite. However, the ruins remained.
https://www.history.com/news/how-the-nazis-tried-to-cover-up-their-crimes-at-auschwitz