Empty canisters of Zyklon B.
Auschwitz I. Block 4.
Zyklon B was a pesticide produced by the Degesch company. It was initially designated for eradicating insects, such as lice.
From late 1941, Zyklon B was also used at Auschwitz to murder people in gas chambers, overwhelmingly Jews who were deported within the extermination program planned by Nazi Germany, but also small groups of prisoners: Polish, Soviet POWs, or Roma and Sinti.
(Photo: https://instagram.com/abbs55)