A woman affected by tear gas is assisted during a May Day protest against austerity measures, in San Juan, Puerto Rico May 1, 2018. (Photo by Alvin Baez/Reuters)

A woman poses with a grenade launcher at a weapons exhibition during festivities marking Marines Day in St.Petersburg, Russia, Saturday, November 24, 2018. (Photo by Dmitri Lovetsky/AP Photo)

Individuals and populations student winner. Limbing in the Tropics, photographed in Manaus, Brazil. While walking in the Amazon rainforest looking for bat roosts to set up mist nets to capture bats for scientific research, a faint and almost imperceptible noise suddenly caught this photographer’s attention. An anteater was climbing with exceptional ability in a tangled mess of branches and lianas. (Photo by Adrià López Baucells/University of Lisbon/British Ecological Society)

Residents wade through flood waters from Tropical Storm Harvey in Beaumont Place, Houston, Texas on August 28, 2017. Houston was still largely paralyzed Monday, and there was no relief in sight from the storm that spun into Texas as a Category 4 hurricane, then parked itself over the Gulf Coast. (Photo by Jonathan Bachman/Reuters)

Four actors on horseback dressed in Game of Thrones related costumes carry the Queen's Baton as they make their way way along the Dark Hedges on August 29, 2017 in Antrim, Northern Ireland. The Dark Hedges near Stranocum in County Antrim featured as the King's Road in season two of Game of Thrones and has become a tourist mecca for fans of the television series along with other filming locations in the province. The Queen's Baton Relay is currently on a tour of the United Kingdom as it makes its way around Europe in preparation for the 2018 Commonwealth Games in Australia. (Photo by Charles McQuillan/Getty Images)

New Orleans police officers try to keep their heads down as they move in on a Black Panther headquarters during an exchange of gunfire in New Orleans on September 15, 1970. The shootout occurred as police moved in to make arrests on Tuesday morning following a series of incidents. (Photo by Jack Thornell/AP Photo)

People fight for the ball as they take part in a mud football match during a festival for celebrating harvest in a village in Jinhua, Zhejiang Province, China September 24, 2017. (Photo by Reuters/China Stringer Network)

People wearing costumes walk during Halloween in Sierra Madre, California, U.S., October 31, 2017. (Photo by Mario Anzuoni/Reuters)