you've actually visited Dachau, which I did in April 2008. It was amazing, and incredibly horrible. You could feel the ghosts, and the evil that made them so. I've watched this episode over a dozen times since then, and as far as I can tell it was made on site, though I can't find any documentation to verify it, but the "entrance" gate (of which there was no other exit) and the detention center had exactly the same dimensions. As did the cell block "sleeping" arrangements. The "main house" looked different on the outside but had the same dimensions and footprint. However the Block 6 prisoner quarter was not/no longer there relative to the main house; but then none of the prisoners "quarters" were, other than a replica of one of a dozen or so in a part of the camp not shown in the episode. Note there are no remains of hangposts that are shown in the episode, but there is the "trench of depth" (my words) that some threw themselves across to deliberately electrocute themselves is still there. Incredible, horrible, and it must NEVER happen again.
And to think this was the first concentration camp (and used as the model for all others, including the supposedly never used incinerators, and DEFINITELY as the training grounds for all the other camp commandants. Yet it was not even made for extermination but for the "confinement" of political prisoners in the mid 1930s Germany - and they (not it) yet killed over 32,000 people boggles the mind about how much evil there was even then, the seed of which obviously grew horrendously.
If you have the opportunity, I strongly recommend you visit Dachau (and the other camps - I thought there were only a dozen or so - in reality there were over 200!). The stories, and photos, and yes videos, that the camp museums told eclipsed what I had seen and read previously, and as I said boggles the imagination. Thank God to Mr. Serling and his backers to have told this story, and in particular using the real context of the actual camp.
Anybody who criticizes this episode as mere drama is a lost, uneducated or misguided soul... As the woman at the beginning of the episode said, and the doctor at the end said - why is it still standing? The answer as Rod Serling said - to paraphrase - because it must.
Dave Williams