A number of people gathered in Poland, marking 72 years since the liberation of Auschwitz.
Friday is International Holocaust Remembrance day.
The goal is to keep the atrocities of the Holocaust in the minds of people around the world, to prevent it from ever happening again.
Congressman Brian Higgins recently paid tribute to a Western New York WWII veteran, who was an eyewitness to the liberation of concentration camps.
Higgins said, "This is a time to mourn the millions of victims of the Holocaust. And it serves as an annual reminder to Americans, and indeed to all humanity, that we must never forget the evil that mankind has visited upon itself."
Six million people were killed by the Nazis during the Holocaust.