A runner in fancy dress participates in the Virgin London Marathon 2013 on April 21, 2013 in London, England. (Photo by Tom Dulat/Getty Images)

Boys pan for gold on a riverside at Iga Barriere, 25 km (15 miles) from Bunia, in the resource-rich Ituri region of eastern Congo February 16, 2009. Ituri is one of many areas of the country to have experienced bitter ethnic conflict between rival tribes in recent years. Massacres have left tens of thousands dead. It is this fighting that led U.S. authorities to take the unprecedented step of naming Congo in section 1502 of the Dodd-Frank financial regulation act, which says U.S.-listed companies that source gold, tungsten, tantalum and tin from Congo or its neighbours must assure the U.S. stock exchange regulator that their business is not helping fund conflict. (Photo by Finbarr O'Reilly/Reuters)

Pictures of deceased people are seen inside a chapel at a cemetery in the village of Smoljinac, Serbia, October 25, 2016. From a distance, the cemetery in the eastern Serbian village of Smoljinac looks like a residential neighbourhood eerily placed among graves. But once inside the grounds, after passing a section with the usual stone slabs, visitors find rows of small bungalows painted in pastel colours. They have one or two rooms, large windows and ornate plaques – some inside, some outside – memorialising the deceased. These are the burial chapels of Smoljinac, cosy cabins with a furnished room inside, a storage place for wreaths and funeral paraphernalia, and the family crypt below. Some even have electric power inside. (Photo by Marko Djurica/Reuters)

A devotee carrying an idol of the Hindu god Ganesh, the deity of prosperity, jumps into the Sabarmati river to immerse the idol during the 10-day-long Ganesh Chaturthi festival in Ahmedabad, India, September 11, 2016. (Photo by Amit Dave/Reuters)

“The Independence day”. While on storm chasing expeditions in the Tornado Alley in USA I have encountered many photogenic supercell storms. This photograph was taken while we were approaching the storm near Julesburg, Colorado on My 28th, 2013. The storm was tornado warned for more than one hour, but stayed an LP storm through all its cycles and never produced a tornado, just occasional brief funnels, large hail and some rain. Photo location: Julesburg, Colorado, USA. (Photo and caption by Marko Korošec/National Geographic Photo Contest)

A fish jumps over a net as a boy works in a fish farm at Htantapin township, outside Yangon, Myanmar February 18, 2016. One in five children in Myanmar aged 10-17 go to work instead of school, according to figures from a census report on employment published last month, and the opening up of the economy since 2011 has triggered a spike in demand for labour. Many children work in fish farming and processing. At Yangon's San Pya fish market, the country's largest, girls and boys as young as nine clean and process fish and unload boats and trucks during 12-hour overnight shifts. (Photo by Soe Zeya Tun/Reuters)

Robot couple Xiaolan (L) and Xiaotao carry trays of food at a restaurant in Jinhua, Zhejiang province, China, May 18, 2015. The restaurant, which opened on Monday, has two robots delivering food for customers. The robots were designed as a couple, Xiaolan and Xiaotao, according to local media. (Photo by Reuters/Stringer)

An ice swimming enthusiast dressed as Neptune takes to the frigid waters of Orankesee lake during the 27th annual "Winter Swimming in Berlin" on January 8, 2011 in Berlin, Germany. A local swimmers' group called the “Berlin Seals” invite ice swimmers from across Germany and abroad to the annual event. Members claim ice swimming is good for the body's blood circulation. (Photo by Sean Gallup)