A cat sits on the empty Great Wall on February 23, 2021 in Beijing, China. Affected by the new coronavirus (COVID-19), the number of visitors to Mutianyu Great Wall in 2020 dropped by about 60%. (Photo by Lintao Zhang/Getty Images)

A man and his son ride a horse at Tahrir Square in Sanaa, Yemen on January 21, 2021. (Photo by Khaled Abdullah/Reuters)

A family takes a picture at the Oscar Myer Wienermobile during a visit to “The Flower Fields”, as California opens up from the pandemic, in Carlsbad, California, U.S., March 31, 2021. (Photo by Mike Blake/Reuters)

Children play in water to beat the heat during the Muslim holy month of Ramadan amid lockdown of the Sindh province due to the ongoing coronavirus COVID-19 disease pandemic in Karachi, Pakistan, 28 April 2020. Muslims around the world celebrate the holy month of Ramadan, by praying during the night time and abstaining from eating, drinking, and sexual acts during the period between sunrise and sunset. Ramadan is the ninth month in the Islamic calendar and it is believed that the revelation of the first verse in Koran was during its last 10 nights. (Photo by Shahzaib Akber/EPA/EFE)

A boy walks by a model of a dinosaur wearing a face mask, during a partial lockdown to prevent the spread of the coronavirus, at the Museum of Natural History in Brussels, Tuesday, May 19, 2020. Museums are hesitantly starting to reopen as the coronavirus lockdown measures are relaxed, yet experts say that one in eight in the world could potentially face permanent closure because of the pandemic. (Photo by Virginia Mayo/AP Photo)

A cafe-restaurant staff stands outside as people drink coffee in Monastiraki district of Athens, on Monday, May 25, 2020. Greece restarted regular ferry services to its islands Monday, and cafes and restaurants were also back open for business as the country accelerated efforts to salvage its tourism season. (Photo by Petros Giannakouris/AP Photo)

A protester wears a face shield made of recycled plastic bottles by artist Leeroy New during a anti-terror bill rally at the University of the Philippines as they observe Independence Day on Friday, June 12, 2020, in Metro Manila, Philippines. Hundreds of activists in the Philippine capital staged protests Friday against a proposed anti-terror law they say could be used to quash dissent, ignoring police threats that they could be arrested for violating coronavirus restrictions against large public gatherings. (Photo by Aaron Favila/AP Photo)

Children are seen on a bike after Muslims in Nigeria perform Eid prayer following the global outbreak of coronavirus disease (COVID-19) in Nasarawa on May 24, 2020. (Photo by Afolabi Sotunde/Reuters)