A police officer wearing a Balinese traditional mask, called celuluk, performs as the new coronavirus during a campaign to wear masks as a precaution against the virus outbreak at a market in Bali, Indonesia, Thursday, May 14, 2020. (Photo by Firdia Lisnawati/AP Photo)

An airplane is silhouetted at sunrise, seen from the suburb of Saint-Cloud, near Paris, France, 08 December 2016. Paris is undergoing a third day pollution spike, prompting the city to limit vehicle circulation. (Photo by Ian Langsdon/EPA)

A girl lights a candle as she marks the anniversary of 2015 Nepal earthquake, at Boudhanath stupa in Kathmandu, Nepal April 25, 2017. (Photo by Navesh Chitrakar/Reuters)

A Kashmiri woman walks on a footbridge as it rains in Srinagar, June 24, 2015. This year's monsoon rains in India are officially forecast to be only 88 percent of the long-term average. (Photo by Danish Ismail/Reuters)

Planned improvements to Rio’s favelas have meant increases in rent, forcing the poorest families into squatting in unoccupied buildings. Photographer Tariq Zaidi visits the Mangueira community favela, less than 1km from the showpiece Maracanã stadium, to see what life is like for the women living there. Here: Victoria, 12, at her home in Mangueira. (Photo by Tariq Zaidi/The Guardian)

Dancers Marion Krebs and Judy Ness, right, pose as batter and catcher in front of the Chicago White Sox dugout before start of game with Detroit at Comiskey Park, Chicago, Ill., September 18, 1959. White Sox won, 1-0, to move within two games of clinching the American League pennant. (Photo by AP Photo)

A photographer tested the concentration of several pairs of dogs as he captured their reactions to treat time in a series of shots. Christian Vieler, 47, of Waltrop, Germany, has been a professional dog photographer since 2016. He came up with the idea of snapping two dogs catching treats simultaneously. Here: Basset Hounds. (Photo by Vieler Photography/Caters News Agency)

“Catch of the Decade”. Can you guess what happened next? Photo location: Katmai National Park, Alaska, USA. (Photo and caption by Aaron Baggenstos/National Geographic Photo Contest)