Photographers gather to take pictures of pilot Andre Borschberg (C) ahead of the take off of Solar Impulse 2-a solar powered plane- in Nanjing, China, May 31, 2015. The world's largest solar-powered airplane, Solar Impulse 2, took off from eastern China's Nanjing on Sunday to continue its round-the-world voyage. The Swiss-made plane left Nanjing's Lukou International Airport at 2:39 in the early morning, with former fighter pilot Borschberg at the controls alone for the entire 8,200-kilometer flight from Nanjing to Hawaii, the toughest leg of its marathon adventure. (Photo by Reuters/Solar Impulse)

A woman walks past servicemen of the self-proclaimed Donetsk People's Republic (DNR), who take part in a rehearsal for the Victory Day parade in Donetsk, Ukraine on May 3, 2018. (Photo by Alexander Ermochenko/Reuters)

A father crosses a road with his twin daughters in Shanghai, China September 28, 2018. (Photo by Aly Song/Reuters)

A girl stretches next to a pram on the embankment of the Moskva river in Moscow on October 18, 2018. The European part of Russia enjoys an unusually warm weather for the season with temperatures reaching up to 22 degrees centigrade. (Photo by Mladen Antonov/AFP Photo)

A participant jumps trying to control a bull during the annual bull taming “Jallikattu” festival in Palamedu village on the outskirts of Madurai in the southern Indian state of Tamil Nadu on January 16, 2020. (Photo by Arun Sankar/AFP Photo)

A female tourist wears a protective face mask on the street, following an outbreak of the coronavirus disease (COVID-19), in Tokyo, Japan on March 10, 2020. (Photo by Hannibal Hanschke/Reuters)

An air plane takes off from the airport as air traffic is effected by the spread of the coronavirus disease (COVID-19) in Frankfurt, Germany, March 16, 2020. (Photo by Kai Pfaffenbach/Reuters)

Ceremonial skulls La Paz, Bolivia on November 6, 2020. Toads are in Bolivia symbols of the soil and of luck. They complement the Ñatitas, skulls of deceased people that are believed to have special powers. People ask them for different favours. The tradition is related to All Saints´ Day. (Photo by Radoslaw Czajkowski/Rex Features/Shutterstock)