One of the most famous pictures of the Holocaust, this from the Warsaw Ghetto Uprising in May 1943. Photo: Wikimedia Commons.

To mark Holocaust Remembrance Day, the Discovery Channel will air a documentary on May 1 that highlights 55,000 testimonies of survivors and witnesses to genocidal events, including the Holocaust.

The collection of testimonies that will be featured in “Liberation Heroes: The Last Eyewitnesses” are part of the USC Shoah Foundation’s Visual History Archive, which is part of the organization director Steven Spielberg founded after filming “Schindler’s List,” according to Deadline. The one-hour documentary is part of the foundation’s 25th anniversary celebration as well as its Stronger Than Hate Initiative.

The project is a “call to action to stand against hate in all forms,” said Discovery CEO David Zaslav. “These stories remind us of what can happen when religious, racial and ethnic hatred is unbridled.”

Andy Friendly, the documentary’s producer, described the film as “a remembrance of the eyewitnesses to one of mankind’s darkest moments” and also “their enduring final plea…to never stand idly by.”

He added, “In the face of the dramatic rise of intolerance around the world, this message is more relevant than ever.”

Friendly’s father, the late Fred Friendly, wrote about the atrocities he saw firsthand at the Mauthausen concentration camp while covering the war as a master sergeant in the Army. Segments of Fred, who was former president of CBS News, reading his historic “Mauthausen Letter” to his family, and a rarely heard radio report from Buchenwald, are included in the documentary.