Gas-masked men of the British Machine Gun Corps with a Vickers machine gun during the first battle of the Somme, 1916. (Photo by General Photographic Agency/Getty Images)

A coach wipes away tears and comforts a girl who was feeling tired during gymnastics lessons at the Shanghai Yangpu Youth Amateur Athletic School in Shanghai, China, May 4, 2016. (Photo by Aly Song/Reuters)

A man dressed as a bear and wearing a protective face mask amid the outbreak of the coronavirus disease (COVID-19) stands in front of a fountain in central Kyiv, Ukraine on August 11, 2020. (Photo by Valentyn Ogirenko/Reuters)

A Palestinian girl wear a face mask during a lockdown imposed following the discovery of coronavirus cases in the Gaza Strip, Thursday, August 27, 2020. On Wednesday Gaza's Hamas rulers extended a full lockdown in the Palestinian enclave for three more days as coronavirus cases climbed after the detection this week of the first community transmissions of the virus in the densely populated, blockaded territory. (Photo by Hatem Moussa/AP Photo)

A woman wearing a protection face mask walks past a mural of a dog in Shanghai, China, 03 September 2020. Daily life in Shanghai is returning to normal while many people still wear protection masks on the street, which are still mandatory in many shopping malls and other public places. (Photo by Alex Plavevski/EPA/EFE)

A woman sits behind a bicycle on a cold winter morning in New Delhi, December 31, 2019. (Photo by Anushree Fadnavis/Reuters)

A South Indian dancer puts finishing touches to his make up as he gets ready to performs a traditional dance during a promotion event for Indian tourism in the Kerala state, in Kolkata, Eastern India, 28 January 2020. (Photo by Piyal Adhikary/EPA/EFE)

Palestinian groom Mohamed abu Daga and his bride Israa wear face masks amid the COVID-19 epidemic, during a photoshoot at a studio before their wedding ceremony in Khan Yunis in the southern Gaza Strip, on March 23, 2020. Authorities in Gaza confirmed on March 22 the first two cases of novel coronavirus, identifying them as Palestinians who had travelled to Pakistan and were being held in quarantine since their return, as the United Nations warned of potential disastrous outcomes to an outbreak given the high poverty rates and weak health system in the coastal strip, under Israeli blockade since 2007. (Photo by Said Khatib/AFP Photo)