A World War II era P-51 Mustang fighter plane stands in front of a modern 747-8 freighter and a 757 passenger jet at The Boeing Company's centennial celebration in Renton, Washington, U.S. July 15, 2016. (Photo by Alwyn Scott/Reuters)

Rajesh Babu, a police officer, wearing a helmet depicting coronavirus, requests a commuter to stay at home during a 21-day nationwide lockdown to limit the spreading of coronavirus disease (COVID-19), in Chennai, India, March 28, 2020. (Photo by P. Ravikumar/Reuters)

A child looks at a polar bear swimming under a water in its enclosure on a hot summer day at Prague Zoo, Czech Republic, July 30, 2015. (Photo by David W. Cerny/Reuters)

A woman looks at a swimmer getting herself warm after the annual Christmas winter swimming competition in the Vltava river in Prague December 26, 2014. (Photo by David W. Cerny/Reuters)

Lutricia Bock of Germany falls down as she performs during the ladies short program at the ISU European Figure Skating Championship in Bratislava, Slovakia, January 27, 2016. (Photo by David W. Cerny/Reuters)

A baby hippo swims under the water in its enclosure at Prague Zoo, Czech Republic, February 24, 2016. The baby was born on January 28, and is yet to be named. (Photo by David W. Cerny/Reuters)

p*rn star Linda Lovelace, who starred in “Deep Throat”, arrives at the Academy Award in Los Angeles, Ca, April 3, 1974. (Photo by AP Photo)

View of an American marine as he lies in a foxhole and whistles at a husky, one of the scouting dogs used during the landing on Guam, August 1944. (Photo by W. Eugene Smith/Time & Life Pictures/Getty Images)