A man is silhouetted in front of the Allianz-Arena as he walks his dogs at sunrise in Munich, southern Germany, Friday, April 10, 2015. (Photo by Peter Kneffel/AP Photo/DPA)

An employee of the National Park Service takes a selfie with President Barack Obama, left, in the background meeting with the crowd after a tour of Everglades National Park on Earth Day, Wednesday, April 22, 2015, in Florida. Obama used the visit to warn of the damage that climate change is already inflicting on the nation's environmental treasures. (Photo by Lynne Sladky/AP Photo)

A brilliant sunset makes for a fun silhouette picture by jumping between sand bars at Shi Shi Beach on the Olympic Peninsula Friday July 17, 2015. (Photo by Bettina Hansen/The Seattle Times)

A fisherman with a close bond to cormorants uses the flock of birds to catch big fish in Li river in Guilin, China. The aquatic birds can be seen perching on a bamboo raft before swooping into the calm water to grasp hold of prey. (Photo by Julia Wimmerlin/Solnet News & Photo Agency)

Monkeys sit along a street during a snowfall in Ayubia, some 75 km north of Islamabad, Pakistan on January 7, 2020. (Photo by Aamir Qureshi/AFP Photo)

Yeshiva School students briefly dance on Grant Street after the menorah lighting outside of the City-County Building for the fifth night of Hanukkah, Thursday, December 26, 2019, in downtown Pittsburgh. (Photo by Alexandra Wimley/Pittsburgh Post-Gazette via AP Photo)

Schoolchildren from local schools take part in the children's races prior to the annual Pancake race in Olney, Buckinghamshire, England, Tuesday, February 25, 2020. Every year women clad in aprons and head scarves from Olney and the city of Liberal, in Kansas, USA, run their respective legs of the race with pancakes in their pans. According to legend, the Olney race started in 1445 when a harried housewife arrived at church on Shrove Tuesday still clutching her frying pan with a pancake in it. (Photo by Alastair Grant/AP Photo)

Steven Busulwa, an animal keeper, runs away from a charging rhino at the Uganda Wildlife Conservation Education Center (UWEC) amid the lockdown as part of the measures taken to prevent the spread of the coronavirus disease (COVID-19), within Wakiso district, in Entebbe, Uganda on April 20, 2020. (Photo by Abubaker Lubowa/Reuters)