The antennas of the European Southern Observatory's Atacama Large Millimeter/Submillimeter Array, also known as ALMA, are set against the splendor of the Milky Way in this picture by Babak Tafreshi. Construction of the full ALMA array is due to be completed in Chile's Atacama Desert in 2013, but the facility is already making scientific observations with a partial array of antennas. (Photo by ESO/B. Tafreshi/TWAN)

An armed man herds his cattle close to the village of Nimini in northern South Sudan, February 8, 2017. In the chaos of South Sudan's civil war, it took three years for Nyagonga Machul to find her lost children. Machul had traveled from her village to the capital when President Salva Kiir, an ethnic Dinka, fired his deputy Riek Machar, a Nuer, in 2013. (Photo by Siegfried Modola/Reuters)

A radiation monitor indicates 114.00 microsieverts per hour near the building housing the plant's No. 4 reactor, center, and an under construction foundation, right, which will store the reactor's melted fuel rods at Tokyo Electric Power Co.'s tsunami-crippled Fukushima Dai-ichi nuclear power plant in Okuma, Fukushima prefecture, Wednesday, March 6, 2013, ahead of the second anniversary of the March 11, 2011 tsunami and earthquake. Some 110,000 people living around the nuclear plant were evacuated after the massive March 11, 2011, earthquake and tsunami knocked out the plant's power and cooling systems, causing meltdowns in three reactors and spewing radiation into the surrounding air, soil and water. (Photo by Issei Kato/AP Photo/Pool)

Tony Appleton, a town crier, announces the royal birth outside the Lindo Wing of St Mary's Hospital after Catherine, Duchess of Cambridge gave birth to a baby boy in central London July 22, 2013. Prince William's wife Kate gave birth on Monday to a baby boy, in the Lindo Wing of St Mary's Hospital, who becomes third in line to the British throne, his office said. The royal baby, the couple's first child, was born at 4:24 p.m. (15:24 GMT), weighing 8 lbs and 6 oz. (Photo by Lefteris Pitarakis/Associated Press)

In this handout image provided by Ogilvy, a burger made from cultured beef, which has been developed by Professor Mark Post of Maastricht University in the Netherlands (pictured) is shown to the media during a press conference on August 5, 2013 in London, England. The in-vitro burger, cultured from cattle stem cells, the first example of what its creator says could provide an answer to global food shortages and help combat climate change, was fried in a pan and tasted by two volunteers. The burger is the result of years of research by Dutch scientist Mark Post, a vascular biologist at the University of Maastricht, who is working to show how meat grown in petri dishes might one day be a true alternative to meat from livestock.The meat in the burger has been made by knitting together around 20,000 strands of protein that has been cultured from cattle stem cells in Post's lab. (Photo by David Parry)

Anti-balaka militia originally sprang up to protect the Christian population of the Central African Republic, but now stand accused of human rights abuses themselves. Last month, the African Union branded militia targeting Muslims in Central African Republic as “terrorists” and said they would be treated as enemy combatants, a day after killing a Congolese peacekeeper and amid deepening international frustration at continuing violence in the impoverished and landlocked country. Photo: A female member of the anti-balaka, a Christian militia, patrols with other militiamen outside village of Zawa April 8, 2014. (Photo by Goran Tomasevic/Reuters)

Jazmin, 6, sister of Jose Luis, receives Isoniazid Preventive Therapy in Carabayllo in Lima, Peru July 14, 2016. At least 30,000 Peruvians are infected with tuberculosis, an ancient disease that killed 1.8 million globally last year, more than AIDS-related and malaria deaths combined. Partners in Health, a Boston-based non-profit that works with Peru's health ministry, offers a simple solution. It trains community volunteers to tend to tuberculosis sufferers in their homes – ensuring patients take medicine daily and helping them navigate the public health bureaucracy. (Photo by Mariana Bazo/Reuters)