Students gather at a distance from the Garissa University College after an attack by gunmen in Garissa, Kenya, Thursday. The attack has injured dozens of people; a siege is ongoing. AP hide caption

itoggle caption AP

A lynching attended by a large mob. Courtesy of the Library of Congress hide caption

itoggle caption Courtesy of the Library of Congress
Courtesy of Liveright Publishing

Alberto Nisman, the prosecutor investigating the 1994 bombing of the Argentine-Israeli Mutual Association community center, talks to journalists in Buenos Aires, Argentina, in 2013. Nisman was found shot dead in his apartment on Sunday. Natacha Pisarenko/AP hide caption

itoggle caption Natacha Pisarenko/AP

World leaders, including, from the left, Israel's Prime Minister Benjamin Netanyahu, Mali's Ibrahim Boubacar Keita, France's Francois Hollande, Germany's Angela Merkel, EU President Donald Tusk and Palestinian President Mahmoud Abbas march in Paris on Sunday to honor the victims of three days of bloodshed. A White House spokesman acknowledged "we should have sent someone with a higher profile." Philippe Wojazer/AP hide caption

itoggle caption Philippe Wojazer/AP

Abu Hamza al-Masri, also known as Mustafa Kamel Mustafa, at a 2002 fundamentalist Islamic conference in London, where he condemned what he called oppression of Muslims in the West. Masri was sentenced Friday in U.S. court to life in prison on terrorism-related charges. Alistair Fuller/AP hide caption

itoggle caption Alistair Fuller/AP

A United Airlines 747-400 taxis at San Francisco International Airport in 2011. A group of flight attendants have filed suit against the airline to contest their firing over their handling of a perceived safety threat. Eric Risberg/AP hide caption

itoggle caption Eric Risberg/AP
Joel Saget/AFP/Getty Images

Cooperative captives conduct afternoon prayers inside a communal cellblock at Camp 6 last month at the U.S. Navy base at Guantanamo Bay, Cuba. Six long-time detainees of the prison have been transferred to Uruguay. Walter Michot/MCT/Landov hide caption

itoggle caption Walter Michot/MCT/Landov