Theresienstadt was an entire Czechoslovakian town that was turned into a show camp to fool outside observers who had become suspicious of what was happening in concentration camps under the Nazis.
Succumbing to pressure following the deportation of Danish Jews to Theresienstadt, the Germans permitted representatives from the Danish Red Cross and the International Red Cross to visit in June 1944. It was all an elaborate hoax. The Germans intensified deportations from the ghetto shortly before the visit, and the ghetto itself was "beautified." Gardens were planted, houses painted, and barracks renovated. The Nazis staged social and cultural events for the visiting dignitaries. Once the visit was over, the Germans resumed deportations from Theresienstadt, which did not end until October 1944.
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Prior to the tour, a council of Jewish elders was set up. This was intended to give the impression that people in the camp were self governing, and were able to make their own choices. They also deported a lot of people from the camp to bring the numbers down, and then immediately following the successful tour, business went on as usual.
The success of the Thersienstadt ruse was so encouraging that the Nazis followed it up by creating an infamous piece of propaganda. They made a ten minute “documentary” about the conditions in the camp. Most of the film has been lost, but there are some small pieces remaining.
I highly recommend taking an hour to watch this documentary.