The third American health worker to contract the Ebola virus in Liberia was an obstetrician at the ELWA hospital, which is run by the missionary group SIM. Ahmed Jallanzo/EPA/Landov hide caption

itoggle caption Ahmed Jallanzo/EPA/Landov

Gravel helps keep the floor level and prevents moisture from seeping up. The floor installers are Jean Pierre (left), a mason, and Daniel Shenyi, operations manager for EarthEnable. Courtesy of EarthEnable hide caption

itoggle caption Courtesy of EarthEnable

American journalist Steven Sotloff (left) talks with Libyan rebels on the Al Dafniya front line on June 2, 2011, in Misrata, Libya. Sotloff was kidnapped in August 2013 near Aleppo, Syria. Etienne de Malglaive via Getty Images hide caption

itoggle caption Etienne de Malglaive via Getty Images

A man walks past burnt vehicles near a railway station after recent shelling in Donetsk, eastern Ukraine, Aug. 29. Maxim Shemetov/Reuters/Landov hide caption

itoggle caption Maxim Shemetov/Reuters/Landov

The Arirang mass festival re-enacts the history of North Korea. The flag depicted in the background was created by audience members holding up cards. Julia Leeb/teNeues hide caption

itoggle caption Julia Leeb/teNeues

An Afghan policeman searches a man at a checkpoint where a NATO soldier was stabbed to death in Kabul on Aug. 20. As U.S. and NATO troops are drawing down in Afghanistan, the Taliban have been stepping up attacks this summer. Shah Marai/AFP/Getty Images hide caption

itoggle caption Shah Marai/AFP/Getty Images

At left, a woman holds the saffron crocus during the saffron harvest in Herat, Afghanistan. At right, saffron flowers are collected in Saint Hippolyte, eastern France. Since the stigmas need to be picked from the flowers by hand, saffron is the world's most expensive spice. Majid Saeedi/Getty Images; Maxppp /Landov hide caption

itoggle caption Majid Saeedi/Getty Images; Maxppp /Landov