An engineer (L) talks to a driver of a dump truck loaded with gold-bearing soil at the Vostochny opencast of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. Polyus Gold International is the largest gold producer in Russia and one of the top 10 gold miners globally by ounces produced, according to the official web site of the company. Olimpiada is Polyus Gold's largest operation. (Photo by Ilya Naymushin/Reuters)

In this July 30, 2014 photo, neighbors help gravely injured Mohammed al-Selek, 39, wounded by an Israeli mortar strike as he lays next to the body of Palestinian journalist Rami Reyan who was killed, in the Shijaiyah neighborhood of the northern Gaza Strip. Al-Selek's life changed forever last July 30, when the shells slammed into his home killing all his three children, his father and six other relatives. A year later, al-Selek, who lost his leg during the airstrike, still struggles to recover and come to terms with his family's loss in the 50-day Israel-Hamas war. (Photo by Adel Hana/AP Photo)

Young Buddhist novice monks play at a Tibetan nomadic summer grazing area on July 24, 2015 on the Tibetan Plateau in Yushu County, Qinghai, China. Tibetan nomads face many challenges to their traditional way of life including political pressures, forced resettlement by China's government, climate change and rapid modernization. The Tibetan Plateau, often called “The Roof of the World”, is the world's highest and largest plateau. (Photo by Kevin Frayer/Getty Images)

U.S. Army helicopters providing support for U.S. ground troops fly into a staging area fifty miles northeast of Saigon, Vietnam, August 28, 1966. Helicopter fuel is stored in the large rubber tanks, foreground. (Photo by Henri Huet/AP Photo)

Pakistan girls make selfies holding a Pakistan-made weapon displayed at the four-day International Defence Exhibition and Seminar (IDEAS) 2016 in Karachi, Pakistan, Wednesday, November 23, 2016. (Photo by Shakil Adil/AP Photo)

Gorillas sit next to a ruler during a photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. During the weigh-in, animals across the zoo have their vital statistics recorded including their height and weight and the information is then shared with zoos across the world to help zookeepers compare important information on thousands of endangered species. (Photo by Neil Hall/Reuters)

A woman picks marigold flowers used to make garlands and offer prayers, before selling them to the market for the Tihar festival, also called Diwali, in Kathmandu, Nepal on October 17, 2017. (Photo by Navesh Chitrakar/Reuters)