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)

A hiker admires the view as Mt. Etna, Europe's largest active volcano, erupts in the background, in the Bove Valley of Etna Park, on the eastern slope of Mt. Etna, in Sicily, southern Italy, Sunday, July 4, 2021. Since Feb. 16, 2021, Mt. Etna has begun a series of eruptive episodes. (Photo by Salvatore Allegra/AP Photo)

Cadets of Tamilnadu Police perform an acrobatic stunt during a full dress rehearsal for the upcoming Republic Day Parade in Chennai on January 24, 2021. (Photo by Arun Sankar/Profimedia/AFP Photo)

A dog wearing ski goggles rides on the back of a man as they both stand in Times Square in New York, USA on January 25, 2021. (Photo by John Angelillo/UPI/Rex Features/Shutterstock)

French model Tiffany Fournier poses for a digital presentation as part of the spring/summer 2021 collections for the Polish fashion house La Metamorphose, in Paris, France, September 26, 2020. (Photo by Charles Platiau/Reuters)

Students on their way home from school play in a river which has risen due to recent seasonal rains, in a remote village in Panca, Aceh province on January 22, 2021. (Photo by Chaideer Mahyuddin/AFP Photo)

Police officers wield their batons against activists from various student unions during a protest march demanding jobs and better education facilities, in Kolkata, India, February 11, 2021. (Photo by Rupak De Chowdhuri/Reuters)

A woman wearing a face mask rides a bicycle with a child, following an outbreak of the coronavirus disease (COVID-19) in Wuhan, Hubei province, China on February 8, 2021. (Photo by Aly Song/Reuters)