Stefan Dobrovolny of Austria and Inigo Munoz Elorza of Spain (R) stand in front of a quad bike during a simulated Mars mission on Tyrolean glaciers in Kaunertal, Austria, August 7, 2015. The Austrian Space Forum is sending some of its researchers to practice weight-less walking in spacesuits on a glacier which resembles the terrain on Mars. (Photo by Dominic Ebenbichler/Reuters)

A man rides his loaded tricycle next to three schoolgirls in Shanghai on December 11, 2015. (Photo by Johannes Eisele/AFP Photo)

Okame Flowering Cherry tree blossoms are seen frozen on Valentine's Day in front of RX3 Compounding Pharmacy in Chester, Virginia, February 14, 2021. (Photo by Kristi K. Higgins/progress-index.com/USA Today Network via Reuters)

Iranian athlete Maryam Toosi practises on the rooftop of her apartment building following the closure of sports facilities as part of measures aimed at containing the COVID-19 coronavirus, in Iran's capital Tehran on May 19, 2020. The coronavirus pandemic has forced the world's athletes to keep fit in confinement. The novel coronavirus has claimed the lives of nearly 7,200 people in Iran, making it the deadliest outbreak in the Middle East. The government ordered the closure of sports facilities in mid-March as part of measures aimed at containing the virus. (Photo by Atta Kenare/AFP Photo)

Two young women pose for a portrait, dressed in robes after collecting their Bachelor degrees in Conakry on October 12, 2020. Presidential elections are to be held on October 18, with incumbent President bidding for a third term in office, defying critics who say he forced through a new constitution this year enabling him to sidestep two-term presidential limits. (Photo by John Wessels/AFP Photo)

Fireworks light up the sky around the White House, Wednesday night, January 20, 2021, in Washington, as part of the festivities after President Joe Biden was inaugurated today. (Photo by Gerald Herbert/AP Photo)

Ride operator Van Mai wears a face mask against the spread of the coronavirus while working at the Playland amusement park at the Pacific National Exhibition, in Vancouver, British Columbia, Friday, July 10, 2020. (Photo by Darryl Dyck/The Canadian Press via AP Photo)