A protester in an Elmo mask dances during the Justice for George Floyd Philadelphia Protest on Saturday, May 30, 2020. Demonstrators took to the streets across the United States to protest the death of Floyd, a black man who was killed in police custody in Minneapolis on May 25. (Photo by Matt Rourke/AP Photo)

A protester in an Elmo mask dances during the Justice for George Floyd Philadelphia Protest on Saturday, May 30, 2020. Demonstrators took to the streets across the United States to protest the death of Floyd, a black man who was killed in police custody in Minneapolis on May 25. (Photo by Matt Rourke/AP Photo)

Chinese artist Kong Ning walks in her costume made of hundreds of orange plastic blowing horns during her art performance raising awareness of the hazardous smog in front of the Drum tower in a historical part of Beijing on a very polluted day December 7, 2015. Kong, whose works include themes related to China's air pollution problem, named her new performance “The Orange Horns Bride Marries the Blue Sky” and presented it dressed in orange, the colour of the second highest pollution alert level issued again in Beijing as hazardous smog blankets the capital. (Photo by Damir Sagolj/Reuters)

Chinese artist Kong Ning poses in a costume symbolizing a butterfly, which is decorated with 365 masks on its wings to represent the number of days in a year, during her performance art at the Badaling section of the Great Wall on the outskirts of Beijing January 1, 2015. Kong, whose works include themes related to China's air pollution problem, named her new performance art “Hua Die” (transforming into a butterfly) and performed it on the first day of the new year as she hopes that China has clean air for this year. (Photo by Kim Kyung-Hoon/Reuters)

A police officer pepper sprays a protester as another protester stands in front of the race director's car during a farmers' protest who attempted to block the stage' s route, during the 16 th stage of the 105 th edition of the Tour de France cycling race, between Carcassonne and Bagneres- de- Luchon, southwestern France, on July 24, 2018. The race was halted for several minutes on July 24 after tear gas was used as protesting farmers attempted to block the route. (Photo by Stephane Mahe/Reuters)

A protester gestures during a “Yellow vest” protest against higher fuel prices during clashes on the Champs-Elysees in Paris, France, November 24, 2018. (Photo by Benoit Tessier/Reuters)

A counter-protester gestures during a Black Lives Matter protest following the death of George Floyd in Minneapolis police custody, in London, Britain, June 13, 2020. (Photo by Simon Dawson/Reuters)

A young protester takes part in a protest near Tahrir Square to call for the fall of Islamist President on January 24, 2012 in Cairo. (Photo by Mohammed Abed/AFP Photo via The Atlantic)