Penny Lawrence at Oxfam House in Oxford, in 2016. Lawrence, who was the U.K. charity's deputy chief executive, stepped down Monday amid a growing scandal over aid workers who paid for sex in Haiti and Chad. Charlotte Ball / Oxfam/Charlotte Ball / Oxfam hide caption
Chadian soldiers rest in the shade of their armored vehicle near Malam Fatori in April 2015, after troops retook the town from Boko Haram. Philippe Desmazes/AFP/Getty Images hide caption
Helmeted Chadian and other African police commandos, armed with dummy rifles hunt down terrorist suspects who've taken hostages in the building, during a US military led Flintlock 2017 law enforcement exercise in Ndjamena Chad, 15 March 2017. Ofeibea Quist-Arcton/NPR hide caption
Hissene Habre, the former president of Chad, waves as he leaves a courthouse in Dakar, Senegal, on June 3. Habre was ousted from Chad in 1990 and has lived in exile in Senegal ever since. Seyllou/AFP/Getty Images hide caption
An armored vehicle used by Boko Haram militants captured by the Nigerian military in Maiduguri, Borno state, late last month. The extremist group appears to be expanding its operations into neighboring countries in an effort to establish an independent Islamic state. EPA/Landov hide caption
Photos of Luanda, Angola, tell a tale of two cities: sprawling poor neighborhoods and a glitzy waterfront. Saul Loeb/Getty Images; Michael Gottschalk/Getty Images hide caption