Wedges of an orange generate enough current and electrical juice – 3.5 volts – to power an LED. The fruit’s citric acid helps electrons flow from galvanized nails to copper wire in this 14-hour exposure. This image was published in September’s Visions of Earth, a trio of photos that appear in each issue of National Geographic. (Photo by Caleb Charland/National Geographic)

“The Tonight Show” host Jimmy Fallon, center, exits the water during the Chicago Polar Plunge, Sunday, March 2, 2014, in Chicago. Fallon joined Chicago Mayor Rahm Emanuel in the event. (Photo by Andrew A. Nelles/AP Photo)

A medical worker wearing a full protective outfit tests a man for Covid-19 symptoms in a street in Wuhan, China, 01 April 2020. Wuhan, the epicenter of the coronavirus outbreak, partly lifted the lockdown allowing people to enter the city after more than two months. According to Chinese government figures over 2,500 people have died of Covid-19 in Wuhan since the outbreak began. (Photo by Roman Pilipey/EPA/EFE)

A model presents a creation during the 2018 Victoria's Secret Fashion Show in New York City, New York, U.S., November 8, 2018. (Photo by Mike Segar/Reuters)

Attendee Ana Niebla arrives in costume as Princess Penny Wise for opening night of the pop culture festival Comic Con International in San Diego, California, U.S., July 17, 2019. (Photo by Mike Blake/Reuters)

A police officer sings as a hearse drives along a street as part of a campaign sponsored by the Colombian police and a funerary home to raise awareness during the new coronavirus pandemic in Envigado, Antioquia, Colombia, on April 1, 2020. More than 20,000 cases of COVID-19 were registered in Latin America and the Caribbean by Wednesday, according to an AFP tally using information provided by national health authorities and the World Health Organization. (Photo by Joaquin Sarmiento/AFP Photo)

In this photograph taken on July 10, 2012, a Pakistani worker pulls on a wire he will connect to a thick chain that will in turn be used to peel away a slab of the outer structure of a beached vessel in one of the 127 ship-breaking plots in Geddani, some 40Kms west of Karachi. (Photo by Roberto Schmidt/AFP Photo)

Participants ride horses, hold spears and wear historic armoured suits of the Middle Ages as they compete during the Saint George international knight tournament in Moscow, Russia, May 3, 2015. (Photo by Maxim Zmeyev/Reuters)