On 14 August 2013, Egypt's army killed hundreds of protestors in Cairo's Rabaa al-Adawiya Square.
They were protesting against a military coup that had taken place a month earlier, in which the democratically elected president, Mohamed Morsi, was ousted.
Sameh Elbarky was in the square that day. He speaks to Ben Henderson.
(Photo: A poster of Egypt's ousted president, Mohamed Morsi, among debris in Rabaa Square. Credit: NurPhoto/Corbis via Getty Images)