In this Monday, June 5, 2017, file photo, an Indian woman walks as se searches for recyclable materials at a garbage dumping site on the outskirts of Gauhati, Assam state, India. (Photo by Anupam Nath/AP Photo)

Medic James E. Callahan of Pittsfield, Mass., gives mouth-to-mouth resuscitation to a dying soldier in war zone D, about 50 miles northeast of Saigon, June 17, 1967. Thirty-one men of the 1st Infantry Division were reported killed in the guerrilla ambush, with more than 100 wounded. (Photo by Henri Huet/AP Photo)

A Monster Jam truck performs a back flip during the first-ever monster truck event in Beijing's iconic “Bird's Nest” National Stadium on Saturday, July 29, 2017. (Photo by Ng Han Guan/AP Photo)

Young girls perform in front of the monument to Soviet state founder Vladimir Lenin during the City Day celebrations in Yekaterinburg, Russia on August 19, 2017. (Photo by Maxim Shemetov/Reuters)

Festival crowd enjoying the weather on Day 1 of Reading Festival on August 25, 2017 in Reading, England. (Photo by Dean Fardell/Barcroft Images)

A protester is sprayed with mace by riot police after throwing a chair through a window of a business during the second night of demonstrations after a not guilty verdict in the murder trial of former St. Louis police officer Jason Stockley, charged with the 2011 shooting of Anthony Lamar Smith, who was black, in St. Louis, Missouri, U.S., September 16, 2017. (Photo by Lawrence Bryant/Reuters)

A Boeing 777-300 from Swiss International Airlines lands on a foggy morning at Zurich Airport, on Friday, October 13, 2017, in Zurich, Switzerland. The high humidity renders the air vortex visible. (Photo by Christian Merz/Keystone via AP Photo)

Villagers offer flowers to a wild tusker, laying dead in a field in Panbari villagein Panbari village on the outskirts of Gauhati, India, Thursday, November 2, 2017. According to a veterinarian the tusker died of food poisoning. Scarcity of food and illegal encroachment of forest areas have forced these wild elephant to move to populated areas for food. (Photo by Anupam Nath/AP Photo)