A demonstrator confronts riot police during a rally in defense of the nationalization of lithium reserves in the country, in Santiago, Chile on January 29, 2018. (Photo by Pablo Sanhueza/Reuters)

Supporters of the United Democratic Party (UDP) opposition alliance presidential candidate, Adama Barrow attend a campaign rally in Buffer zone, Gambia November 29, 2016. (Photo by Thierry Gouegnon/Reuters)

An internally displaced Afghan girl holds a child at a refugee camp in Kabul, Afghanistan May 31, 2016. (Photo by Mohammad Ismail/Reuters)

Nubian women sell traditional handicrafts at the Nubian Gharb Suheil village, near Aswan south of Egypt, October 1, 2015. For half a century, Egypt's Nubians have patiently lobbied the government in Cairo for a return to their homelands on the banks of the upper Nile, desperate to reclaim territory their ancestors first cultivated 3,000 years ago. (Photo by Mohamed Abd El Ghany/Reuters)

The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on July 21 as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, located 62 feet below the surface of the Atlantic Ocean in the Florida Keys National Marine Sanctuary. The NEEMO 21 crew will perform research both inside and outside the habitat during a 16-day simulated space mission. During simulated spacewalks carried out underwater, they will evaluate tools and mission operation techniques that could be used in future space missions, including journeys to Mars. (Photo by Karl Shreeves/NASA)

A man sleeps on a wheelbarrow outside a closed shop at a market during the first day of a ceasefire in Yemen's capital Sanaa April 11, 2016. (Photo by Khaled Abdullah/Reuters)

Interior designer Zahra Afridi (R) kicks a punching bag during a kickboxing training session at her home in Islamabad February 10, 2014. Afridi runs her own interior design company. Her most recent project was a Classic Rock Coffee cafe in Islamabad. Though instability continues to plague Pakistan and many areas are dominated by social conservatism, some of the country's more affluent residents have worked to fashion a very different kind of lifestyle for themselves. Pictures of men and women taking part in all sorts of activities and professions – from being a pilates instructor, to a textile retail entrepreneur, to a member of a rock band – offer a different view of Pakistan to images of conflict that often make the news. (Photo by Zohra Bensemra/Reuters)

An American Marine readies to land on Guadalcanal during the five-month struggle for the island between late 1942 and early 1943. Three thousand miles south of Tokyo, Guadalcanal was a major shipping point for military supplies. The Allied victory there in February, 1943, marked a major turning point in the war after a string of Japanese victories in the Pacific. (Photo by Joe Scherschel/Time & Life Pictures)