Thousands of Egyptian protesters marched Tuesday in Cairo to mark one year since the Maspero Massacre, when nearly 30 people were killed in a Coptic Christian demonstration that was violently crushed by security forces, International Christian Concern reports. "The victims of the massacre are described ... as martyrs," Egypt Independent reported. "Among [Coptic Christians], this language of martyrdom has a particular resonance, rooted in a history of struggle as the practitioners of a minority faith in Egypt." Most of the victims' families, however, have yet to see justice: "The Egyptian authorities have failed to conduct a full impartial and independent investigation into the circumstances of the violence and to bring those responsible to account," according to Amnesty International. The massacre on Oct. 9, 2011, later dubbed "Bloody Sunday," marked the largest attack on Egyptian Christians in recent memory and the worst violence in the country since the overthrow of president Hosni Mubarak in February 2011.