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 model presents a creation by Singapore-born designer Andrew GN as part of his Fall/Winter 2016/2017 women's ready-to-wear collection show in Paris, France, March 4, 2016. (Photo by Benoit Tessier/Reuters)

Actor Chantel Jeffries attends the 2018 Billboard Music Awards at MGM Grand Garden Arena on May 20, 2018 in Las Vegas, Nevada. (Photo by Steve Marcus/Reuters)

Actress Olivia Munn attends the 2018 MTV Movie And TV Awards at Barker Hangar on June 16, 2018 in Santa Monica, California. (Photo by Mario Anzuoni/Reuters)

British singer and actress Rita Ora performs on the stage at Sporting Summer Festival in Monaco on Tuesday, August 7, 2018. (Photo by Andrew Timms/Rita Ora Instagram)

Kendall Jenner (R) attends Casamigos Halloween party at CATCH Las Vegas at ARIA Resort & Casino on October 27, 2018 in Las Vegas, Nevada. (Photo by Bryan Steffy/Getty Images for Casamigos)

Leigh-Anne Pinnock of Little Mix attends the MTV EMAs 2018 at Bilbao Exhibition Centre on November 4, 2018 in Bilbao, Spain. (Photo by Jeff Kravitz/FilmMagic)