Slave laborers at the Dora Concentration Camp building V2 rockets for Wernher Von Braun. More: http://www.dora.uah.edu/slavelabor.html
These photos were taken by a Nazi-sanctioned photographer for propaganda purposes (note the staging, skilled rather than manual labor, clean clothes, relatively healthy-looking prisoners), and they’re still painful to look at. I can’t imagine how horrific the reality was.
At a minimum, 20,000 laborers died constructing V-2s. At the Mittelwerk underground factory in Kohnstein, 250 laborers died per day.