Yad Vashem has an exhibition called “And You Shall Tell Your Children,” which shows “some of the ways Passover was observed throughout Europe prior to the Holocaust, during the Holocaust years, and in the displaced persons camps and children’s homes following the war.”
Here is just a sample of the photos taken during the Holocaust.

Yad Vashem Archives FA33/1862

Yad Vashem Archives FA33/186

Yad Vashem Photo Archives 37CO7

Yad Vashem Archives
See the whole thing.
As we are about to enter Passover over 70 years later, it is truly a sobering thought to realize there are plenty of people out there who would love to replicate the Holocaust.