Participants take part in the annual Great Spitalfields Pancake Race in aid of London's Air Ambulance in London, Britain February 9, 2016. (Photo by Stefan Wermuth/Reuters)

In this September 27, 2017 file photo, girls walk past a wall riddled with bullet holes from shootings between rival drug traffickers, at the Rocinha slum, in Rio de Janeiro, Brazil. Violence is on the rise in Rio's slums after several years of decline, and the killings of kids have shocked even residents long inured to deaths from gangs and police. (Photo by Silvia Izquierdo/AP Photo)

In this April 18, 2019 photo, tattoo artist Lalo Calva inks a tattoo on client Adrian Alonso Rodriguez, a journalist, announcer and dubbing artist, at the Corona Tattoo parlor in Mexico City. Not only inks and techniques have changed in Mexico over the years, but tattoos themselves have evolved from stigmatized symbols of gangs, violence and poverty to an art form. (Photo by Marco Ugarte/AP Photo)

Handout photo dated March 20, 2015 issued by Chester Zoo of lemurs looking at the eclipse over Chester Zoo. (Photo by Steve Rawlins/PA Wire/Chester Zoo)

Revellers celebrate New Year's Day in central Moscow, Russia, January 1, 2016. (Photo by Tatyana Makeyeva/Reuters)

Police are highly visible at the Notting Hill carnival with several arrests, stop and search and a “knife detection gate” in operation, August 27, 2018 in west London, England. 133 arrests were made at the carnival yesterday with 20 knives seized. (Photo by South West News Service/Action Press/Picturedesk)

Cave Diver, Anhumas Abyss, Bonito, Brazil: The Anhumas Abyss is an underground cavern with a crystal-clear lake below, more than 260 feet (79 m) deep. A visitor must enter through a narrow opening at the top of the chamber and rappel into the cave. Snorkeling and scuba diving in the lake reveal amazing scenery. Distinctive, conical limestone stalagmites and stalactites occupy the lake and the surrounding area, some reaching 65 feet (20 m) high. (Photo by Marcio Cabral/Nature’s Best Photography Awards 2017)