Foemer prisoner's cells at the Tuol Sleng Genocide Museum (S21).

A view through a cell door at the Tuol Sleng Genocide Museum (S21).

Implements of torture at the Tuol Sleng Genocide Museum (S21).

The perimeter fence at Auschwitz concentration camp.

The perimeter fence at Auschwitz concentration camp.

People gather for a rally on the 100th anniversary of the Armenian genocide.

People gather for a rally on the 100th anniversary of the Armenian genocide.

Anti-Nazi activists Beate and Serge Klarsfeld at the Holocaust Memorial in Berlin.

Anti-Nazi activists Beate and Serge Klarsfeld at the Holocaust Memorial in Berlin.

Anti-Nazi activist Beate Klarsfeld at the Holocaust Memorial in Berlin.

A woman cycles past a mural of war criminal Ratko Mladic.

A woman cycles past a mural of war criminal Ratko Mladic.

Mamtaj Begum, (27) is a survivor of the Tula Toli massacre, a mass-killing of Rohingya during a Myanmar Army led clearance operation at the village of Tula Toli (Min Gyi) in the Rakhine State, close t...

Rajuma Begum (20) is a survivor of the Tula Toli massacre, a mass-killing of Rohingya during a Myanmar Army led clearance operation at the village of Tula Toli (Min Gyi) in the Rakhine State, close to...

Hasina Begum, right, with her sister-in-law, Asma Begum. They are survivors of the Tula Toli massacre, a mass-killing of Rohingya during a Myanmar Army led clearance operation at the village of Tula T...