Arrivals at Sobibor stepped off the trains to see Tyrolean-style cottages, painted signs, crisp curtains and geraniums in window boxes. This episode examines how that facade was engineered by architect Richard Thomalla as part of Operation Reinhard to keep victims calm and let SS guards compartmentalize the murder of between 170,000 and 250,000 people. We walk through the isolated zones, the pine branches woven through barbed wire to block sightlines, Hermann Michel's reassuring speech in a white doctor's coat, and the camouflaged path the SS called the Himmelstrasse that led to gas chambers powered by a tank engine's exhaust.

The episode then turns to the roughly 600 prisoners kept alive to run the machinery, from luggage sorters and barbers to the Sonderkommando of Lager III, none of whom survived. We look at small acts of defiance like S ...