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)

Breitling Wingwalkers aircrafts perform during an aerobatic display at an air show in Zhengzhou, Henan province, China, September 25, 201. (Photo by Reuters/Stringer)

The Jet Propulsion Lab team's RoboSimian robot turns on a valve at a simulated disaster-response course during day one of the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge finals in Pomona, California, June 5, 2015. (Photo by David McNew/Reuters)

A boy looks on as fire fighters try to extinguish the fire at oil wells, were set on fire by Daesh terrorists as they fled after Al Qayyarah town's cleansing from Daesh militants as the operation to retake Iraq's Mosul from Daesh continues, in Al Qayyarah Town of Mosul, Nineveh, Iraq on November 02, 2016. (Photo by Yunus Keles/Anadolu Agency/Getty Images)

Ballet dancer and performer Ashlee Montague of New York wears a gas mask while she dances in Times Square as the coronavirus disease (COVID-19) outbreak continued in Manhattan, New York City, U.S., March 18, 2020. (Photo by Andrew Kelly/Reuters)

A general view of Copacabana beach during the coronavirus disease (COVID-19) outbreak in Rio de Janeiro, Brazil, March 22, 2020. (Photo by Ricardo Moraes/Reuters)

An internally displaced Afghan girl plays outside her shelter, amid the spread of the coronavirus disease (COVID-19), in Kabul, Afghanistan on May 7, 2020. (Photo by Mohammad Ismail/Reuters)

Su-25 jet fighters release smoke in the colours of the Russian state flag over Red Square during a flypast rehearsal ahead of a parade on Victory Day, which marks the anniversary of the victory over Nazi Germany in World War Two, in Moscow, Russia on May 5, 2021. (Photo by Shamil Zhumatov/Reuters)