A heat-stressed koala waits as a resident pours water on its back on December 19, 2015 in Adelaide, Australia. Adelaide is experiencing an extreme heatwave, with temperatures reaching over 40 degrees for five consecutive days. (Photo by Morne de Klerk/Getty Images)

Demonstrators protest the shooting death of Alton Sterling near the headquarters of the Baton Rouge Police Department in Baton Rouge, Louisiana, U.S. July 9, 2016. (Photo by Jonathan Bachman/Reuters)

Civilians, who fled the violence in Manbij city, arrive to the southeastern rural area of Manbij, in Aleppo Governorate, Syria June 19, 2016. (Photo by Rodi Said/Reuters)

Model/actress Chantel Jeffries attends L.A. Hearts + PacSun celebrate 2017 Spring Swimwear Collection at Delilah on January 25, 2017 in Los Angeles, California. (Photo by Rochelle Brodin/Getty Images for L.A. Hearts/PacSun)

Participants from Newar community in traditional attire, dance during the Newari New Year parade that falls during the Tihar festival, also called Diwali, in Kathmandu, Nepal October 31, 2016. (Photo by Navesh Chitrakar/Reuters)

Members of p*ssy Riot perform in concert during Day For Night festival on December 16, 2017 in Houston, Texas. (Photo by Gary Miller/Getty Images)

A US Marine leads two Viet Cong suspects in restraints during the Tet Offensive on February 20, 1967. (Photo by Bettmann Archive/Getty Images)

In this Monday, March 18, 2019 photo, a street artist performs in Caracas, Venezuela. Venezuelans are facing a severe economic and political crisis as President Nicolas Maduro has remained in power despite heavy pressure from the United States and other countries arrayed against him, managing to retain the loyalty of most of Venezuela's military leaders. (Photo by Natacha Pisarenko/AP Photo)