A dozen rare color photos and an accompanying video from the Nazis’ first concentration camp, Dachau, were released to the Internet. The images, said to be from 1933 — the year the camp was created — were posted Sunday on the Vintage Everyday photo site without attribution.

The photographs were authenticated by an expert quoted in the Daily Mail, who said they were “quite similar” to photos taken by US soldiers after they liberated Dachau in 1945.

Dachau was in operation from 1933-45 and served as a template for other concentration camps operated by the Third Reich. It primarily housed various types of political prisoners, criminals, Catholics and Jews.

While not an “extermination camp” like Auschwitz, the prisoners were worked mercilessly. Nazi records show some 31,000 official deaths during the years that the the work camp was operational, but the total number of prisoner deaths are unknown.