Iraqis run for cover as they flee Mosul's Al-Tayaran neighbourhood on February 28, 2017, during an offensive by Iraqi forces to retake the area from Islamic State (IS) group fighters. Hundreds of civilians fled through the desert to escape fighting and privation in Mosul, joining thousands of others who left their homes as conditions worsen in the city's west. (Photo by Ahmad Al-Rubaye/AFP Photo)

A student shouts slogans against Venezuelan President Nicola Maduro during a protest on the main highway in Caracas on March 30, 2017. Venezuela' s Supreme Court took over legislative powers Wednesday from the opposition- majority National Assembly, whose speaker accused leftist President Nicolas Maduro of staging a “coup”. (Photo by Juan Barreto/AFP Photo)

Sergei Bobkov, 59, paints Siberian cedar nut oil onto a life-size sculpture of Pallas's Cat, also known in Russia as Manul Cat, which he made from Siberian cedar wood shavings using more than 700 thousand pieces over four years, in the village of Kozhany, southwest of the Siberian city of Krasnoyarsk, Russia, April 28, 2017. (Photo by Ilya Naymushin/Reuters)

Visitors look at tropical fish transported from Japan's southern island of Okinawa displayed in a giant 14-ton fish tank at the Sony Square event space in Tokyo on July 17, 2016. The 45-day-long summer exhibition will be held through August 28 to display sea creatures common to the waters around Okinawa. (Photo by Kazuhiro Nogi/AFP Photo)

In this June 6, 1966 file photo, civil rights activist James Meredith pulls himself across Highway 51 after being shot in Hernando, Miss. Meredith, who defied segregation to enroll at the University of Mississippi in 1962, completed the march from Memphis, Tenn., to Jackson, Miss., after being treated for his wounds. (Photo by Jack Thornell/AP Photo)

A Bangladeshi girl watches from a nearby building after a five-story building was raided by police in Dhaka, Bangladesh, Tuesday, July 26, 2016. Police in Bangladesh's capital raided a five-story building Tuesday that was used as a den by suspected Islamic militants, killing nine of them, the country's police chief said. Police said they belonged to a Bangladeshi group blamed for an attack on a Dhaka cafe earlier this month in which 20 hostages, mostly foreigners, were killed and had been planning another large-scale assault. (Photo by AP Photo)

A news reporter doing a stand up near a sea wall in Cedar Key, Fla., is covered by an unexpected wave as Hurricane Hermine nears the Florida coast, Thursday, September 1, 2016. Hurricane Hermine gained new strength Thursday evening and roared ever closer to Florida's Gulf Coast, where rough surf began smashing against docks and boathouses and people braced for the first direct hit on the state from a hurricane in over a decade. (Photo by John Raoux/AP Photo)

Mystical Forest. Tracey Jennings photographed this seven-gill shark in a kelp forest just off the shore of Simon's Town near Cape Town, South Africa. You don't need to travel far from cities to visit Narnia. This 7 gill shark was photographed in a kelp forest just off the shore of Simonstown near Cape Town, South Africa. (Photo by Tracey Jennings/National Geographic Travel Photographer of the Year Contest)