People take a photo next to a blooming tree during cherry blossom season in Yuyuantan Park in Beijing, China on March 31, 2021. (Photo by Thomas Peter/Reuters)

Elephants cool off at a zoo in Karachi, Pakistan, 31 March 2021. Caretakers at Karachi's zoo were working to keep animals cool during a heatwave affecting southern Pakistan. (Photo by Shahzaib Akber/EPA/EFE)

A prong extending from a remote-controlled robot prototype approaches the mouth of a volunteer to extract a throat swab sample, as part of a self-funded project to assist physicians in running tests on suspected COVID-19 coronavirus patients in a bid to limit human exposure to disease-carriers, at a private hospital in Egypt's Nile delta city of Tanta, on March 20, 2021. (Photo by Khaled Desouki/AFP Photo)

A man smokes a marijuana cigarette to celebrate 420, in Times Square amid the coronavirus disease (COVID-19) pandemic in New York City, New York, U.S., April 20, 2021. (Photo by Carlo Allegri/Reuters)

These friends took a tumble after sharing a hug in Leeds in northern England on May 17, 2021, as Covid-19 lockdown restrictions ease. (Photo by London News Pictures)

A police officer wields his baton against a man as a punishment for defied curfew due to rise of COVID-19 coronavirus cases in Nagaon District of Assam, India on May 16, 2021. (Photo by Anuwar Hazarika/NurPhoto via Getty Images)

Members of the Loktev Ensemble perform during the opening of the 18th Moscow Meets Friends International Festival at the Moscow International House of Music in Moscow, Russia on May 18, 2021. (Photo by Artyom Geodakyan/TASS)

United States Air Force Academy graduates cheer as the United States Air Force Thunderbirds fly over the graduation for the Class of 2021 at Falcon Stadium on May 26, 2021 in Colorado Springs, Colorado. Chairman of the Joint Chiefs of Staff General Mark A. Milley gave the commencement address to the 1,019 graduates from the academy. (Photo by Michael Ciaglo/Getty Images)