An aerial view shows a Russian Troika, a sledge drawn by three horses, competing on the ice-covered Yenisei River during the annual Ice Derby amateur horse race near the Siberian settlement of Novosyolovo, south of Krasnoyarsk, Russia March 17, 2018. (Photo by Ilya Naymushin/Reuters)

A U.S. Army crew chief flying on board a CH-47F Chinook helicopter observes the successful test of flares during a training flight in Afghanistan, March 14, 2018. (Photo by Tech. Sgt. Gregory Brook/Reuters/U.S. Air Force)

People protest at the Boston Free Speech Rally in Boston, USA on August 19. 2017. With the Boston Free Speech rally was closed to the media (despite the Boston Common being a public space), a lot of the media’s coverage centred on the tensions within the larger counter-protest. (Photo by Stephanie Keith/Reuters)

The “Rabid Transit” Burning Man art car erupts with flames from it's onboard propane poofers during the 4th day of the annual Burning Man arts and music festival in the Black Rock Desert of Nevada, U.S., August 31, 2017. (Photo by Jim Bourg/Reuters)

Rohingya refugee children pictured in a camp in Cox's Bazar, Bangladesh, September 19, 2017. With a mass exodus of Rohingya Muslims sparking accusations of ethnic cleansing from the United Nations and others, Myanmar leader Aung San Suu Kyi on Tuesday said her country does not fear international scrutiny and invited diplomats to see some areas for themselves. (Photo by Cathal McNaughton/Reuters)

A Hindu devotee ululates as she holds a banana tree trunk after taking a dip in the waters of the Ganges river during a ritual as part of the Durga Puja festival in Kolkata, India, September 27, 2017. (Photo by Rupak De Chowdhuri/Reuters)

An H-2A rocket carrying Japan's fourth and final quasi-zenith satellite, the Michibiki No. 4, lifts off from the Tanegashima Space Center in Kagoshima Prefecture, southwestern Japan in this photo taken by Kyodo on October 10, 2017. (Photo by Reuters/Kyodo News)

A Syrian Democratic Forces (SDF) female fighter's braid is pictured while she is carrying her weapon in Tal Samin village, north of Raqqa city, Syria November 19, 2016. (Photo by Rodi Said/Reuters)