A boy moves away as a United Nations World Food Programme (WFP) helicopter lands in Rubkuai village, Unity State, northern South Sudan, February 18, 2017. South Sudan on Monday declared famine in some parts of the country, with more than three years of war leaving nearly five million hungry in what aid groups called a “man-made” tragedy. (Photo by Siegfried Modola/Reuters)

Vendors selling vegetables wait for customers under a flyover in the early morning in Ahmedabad, India on February 1, 2017. (Photo by Amit Dave/Reuters)

An Indian Runner duck searches for food on a snow-covered meadow in Aitrang, southern Germany, Wednesday. April 19, 2017. (Photo by Karl-Josef Hildenbrand/DPA via AP Photo)

Snow falls as a woman walks her dog in the village of Podolye, 70 kilometers (43 miles) east of St. Petersburg, Russia, early Thursday, May 11, 2017. North winds brought snow to the east of the St. Petersburg region. (Photo by Dmitri Lovetsky/AP Photo)

Radio City Music Hall Rockettes perform after days of rehearsal and routine polished to perfection at the Radio City Music Hall in New York City on July 26, 1949. (Photo by Ivan Dmitri/Getty Images)

A soldier walks on the bank of the river in central Pyongyang, North Korea on April 16, 2017. (Photo by Damir Sagolj/Reuters)

Kamaz Russian driver Eduard Nikolaev, co- driver Evgeny Yakovlev and mechanic Vladimir Rybakov compete during the 2018 Dakar Rally' s Stage 13 between San Juan and Cordoba in Argentina, on January 19, 2018. (Photo by Franck Fife/AFP Photo)

A man looks inside an overturned truck after an accident along the road between Nouahibou and Nouakchott, Mauritania December 3, 2009. (Photo by Rafael Marchante/Reuters)