In this December 13, 2014 photo, Ricardo Alegria holds his donkeys by a leash as he yells to sell their milk in the streets of Santiago, Chile. Alegria, along with his brother Marco, has been selling fresh donkey milk for the past 25 years, and says it's recommended as a vitamin boost. Shot glass size cups of the drink sell for about $2 dollars. Half a liter, which is the most he says his donkeys can give in one day, sells for about $20 dollars. (Photo by Luis Hidalgo/AP Photo)

A prototype battery-powered plane, called Greased Lightning or GL-10 is pictured flying at NASA's Langley Research Center in this undated handout photo obtained by Reuters May 1, 2015. The plane, which has 10 engines and can take off like a helicopter and fly efficiently like an aircraft, is currently in the design and testing phase. (Photo by Reuters/NASA)

The first autonomous and electric shuttle of PostAuto Schweiz in the old village of Sion, Switzerland, June 2016. (Photo by Ruben Sprich/Reuters)

Burning effigies of winter during a celebration of Maslenitsa festival (Pancake Week) at the Etnomir (Ethnoworld) cultural and educational center in Kaluga Region, Russia on March 1, 2020. The holiday celebrates the end of winter and marks the arrival of spring. (Photo by Sergei Bobylev/TASS)

Models prepare backstage before presenting creations of Belarussian designer Tatyana Efremova during the Belarus Fashion Week in Minsk, Belarus, 14 April 2018. (Photo by Tatyana Zenkovich/EPA/EFE)

Brazilian model and actress Alessandra Ambrosio seen wearing a Gucci fanny pack and boots from Dior on April 15, 2018 in Indio, California. (Photo by Timur Emek/GC Images)

Mariam Emad from Parkour Egypt “PKE” practices her parkour skills around buildings on the outskirts of Cairo, Egypt on July 20, 2018. A group of Egyptian women gather at an abandoned park in a Cairo suburb once a week, climbing walls and jumping around in the strenuous physical discipline known as Parkour, while also challenging the country's conservative social norms. (Photo by Amr Abdallah Dalsh/Reuters)

A participant in costume and make-up poses for a photo during a Halloween parade at Walibi park in Wavre, Belgium, October 31, 2018. (Photo by Yves Herman/Reuters)