People take cover as riot police use pepper spray projectile during a protest as a second reading of a controversial national anthem law takes place in Hong Kong, China on May 27, 2020. (Photo by Tyrone Siu/Reuters)

Police spraying protesters with pepper spray inside Central Station after a Black Lives Matter rally in Sydney, Australia, 06 June 2020, a protest against the deaths of Aboriginal people in custody and solidarity with the US protests for George Floyd. (Photo by James Gourley/EPA/EFE)

A participant, surrounded by red chilli peppers, takes part in a chilli-eating competition at a hot spring in Yichun, Jiangxi province, China on December 9, 2018. (Photo by Chen Fei/China News Service via Reuters)

Two robotic legged squad support system (LS3) machines by the Defense Advanced Research Project Agency follow a technician during a demonstration at Joint Base Myer-Henderson Hall, Virginia, on September 10, 2012. (U.S. Marine Corps photo by Sgt. Mallory S. VanderSchans via The Atlantic)

U.S. Army soldiers with the 1st Battalion, 501st Infantry Regiment deployed to Combat Outpost Sabari, Afghanistan scan their area as they begin a multi-day air assault mission near the Pakistani border of eastern Afghanistan's Khost province May 2, 2012. (Photo by Staff Sgt. Joshua L. DeMotts/U.S. Air Force)

U.S. Air Force Major Paul “Loco” Lopez performs in an F-22 Raptor during the AirPower Over Hampton Roads JBLE Air and Space Expo at Joint Base Langley-Eustis, Virginia, U.S. May 18, 2018. (Photo by U.S. Air Force/Staff Sgt. Areca T. Bell/Handout via Reuters)

U.S. Army Sgt. Patricia Foust receives a free Christmas tree on December 7, 2011 at Fort Carson in Colorado Springs, Colorado. More than 600 soldiers and military families at the base chose trees as part of the annual Trees for Troops program. (Photo by John Moore/Getty Images)

Tech. Sgt. Milo Hinson, 3rd Combat Camera Squadron, uses a flashlight while shooting a Berretta 9mm during the night-fire portion of Advance Weapons, Tactics and Techniques training in San Antonio. During night-fire training, airmen learn how to tactically illuminate targets with flashlights and practice using night vision goggles. (Photo by Staff Sgt. Jonathan Snyder/U.S. Air Force). 2011