A Mai-Mai rebel soldier shows off his guns at a checkpoint near the Mugunga refugee camp in Zaire; 1996. (Photo by Carol Guzy/The Washington Post)

Artist Heather Dewey-Hagborg's 'Stranger Visions', comprising of 3D printed faces extracted from DNA taken from discarded cigarette butts and chewing gum, is displayed at the Big Bang Data exhibition at Somerset House on December 2, 2015 in London, England. The show highlights the data explosion that's radically transforming our lives. It opens on December 3, 2015 and runs until February 28, 2016 at Somerset House. (Photo by Peter Macdiarmid/Getty Images for Somerset House)

In this Wednesday, March 18, 2015 photo, limestone quarry workers walk through a cloud of dust spewed into the air by rotor blades of the stone-cutting machinery in the desert of Minya, southern Egypt. Around 45,000 people, including children, work in an estimated 1,500 quarries, digging out stones that later will be used in construction or powdered to be used by pharmaceutical and ceramic companies. (Photo by Mosa'ab Elshamy/AP Photo)

In this Tuesday, June 4, 2019, photo, a Yamanote Line train travels above commuters walking across the crossing during evening rush hours in the Shinjuku district of Tokyo. Operated by the East Japan Railway Co., the Yamanote Line in Tokyo makes a loop around the center of the city, connecting 29 stations that include key stops such as Shinjuku, Shibuya and Ikebukuro. A complete loop of about an hour offers scenes of Japanese daily lives. (Photo by Jae C. Hong/AP Photo)

People ride a prototype of a driverless vehicle as it is moves through a pedestrian area in Greenwich, east London, February 11, 2015. Britain has begun testing driverless cars in four cities, launching the first official trials ahead of a series of planned rule reviews to accommodate the new technology. (Photo by Suzanne Plunkett/Reuters)

Indonesian air force personnel carry the flight data recorder of the ill-fated AirAsia Flight 8501 that crashed in the Java Sea, at airport in Pangkalan Bun, Indonesia, Monday, January 12, 2015. Divers retrieved one black box Monday and located the other from the AirAsia plane that crashed more than two weeks ago, a key development that should help investigators unravel what caused the aircraft to plummet into the Java Sea. (Photo by Achmad Ibrahim/AP Photo)

A Munduruku Indian child is pictured at the Planalto Palace, where a meeting with Minister of the General Secretariat of the Presidency of Brazil Gilberto Carvalho was being held with other Munduruku Indians, in Brasilia, June 4, 2013. President Dilma Rousseff's government sought on Tuesday to defuse mounting conflicts with indigenous groups over its decision to stop setting aside farm land for Indians and plans to build more hydroelectric dams in the Amazon. The government flew 144 Munduruku Indians to Brasilia for talks to end a week-long occupation of the controversial Belo Monte dam on the Xingu river, a huge project aimed at feeding Brazil's fast-growing demand for electricity. (Photo by Ueslei Marcelino/Reuters)

In this September 30, 2013 photo, farmers wait for customers next to their 1950s Chevrolet loaded with garlic for sale at the 114th Street Market on the outskirts of Havana, Cuba. The market s bustle is a result of economic reforms begun in 2010 by President Raul Castro, which includes relaxing rules on private farming. (Photo by Ramon Espinosa/AP Photo)