Afghan children play on the remains of a Soviet-era armored personnel carrier on the outskirts of Jalalabad on February 15, 2016. Soviet troops withdrew from Afghanistan on February 15, 1989, after ten years of fighting against Mujahidin militiamen. (Photo by Noorullah Shirzada/AFP Photo)

Aerial view of a boat working in the green water of Taihu Lake covered by blue-green algae, Wuxi city, Jiangsu province, China on May 23, 2018. (Photo by Imaginechina/Rex Features/Shutterstock)

The northern lights, or aurora borealis, illuminate the sky over Flakstad beach on Lofoten Islands in the Arctic Circle on September 5, 2017. (Photo by Jonathan Nackstrand/AFP Photo)

A model waits backstage before participating in AFI Joburg Fashion Week show with the theme #AfroAsia, in Johannesburg, South Africa October 4, 2018. Picture taken October 4, 2018. (Photo by Siphiwe Sibeko/Reuters)

An Exmoor wild goat silhouetted in the sky over the Bristol Channel at the valley of the Rocks, North Devon, as the UK's heat wave continues on July 19, 2018. (Photo by Paul Silver/South West News Service)

Mount Whaleback iron ore mine 23°21’32.3”S, 119°40’40.1”E. The Mount Whaleback Iron Ore Mine in the Pilbara region of Western Australia. Roughly 98% of the world’s mined iron ore is used to make steel and is thus a significant component in the construction of buildings, automobiles, and appliances such as refrigerators. (Photo by Daily Overview/DigitalGlobe, a Maxar Company)

A Palestinian man argues with an Israeli soldier during clashes over an Israeli order to shut down a Palestinian school near Nablus, in the occupied West Bank, October 15, 2018. (Photo by Mohamad Torokman/Reuters)

Fishermen catch fish at Mao'er lake at the start of winter fishing season which is a local custom to welcome the new year on December 29, 2018 in Huaian, Jiangsu Province of China. (Photo by VCG/VCG via Getty Images)