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)

Indonesian army soldier Partika Subagyo, wearing a costume of the puppet character Bima, dances to raise money for landslide victims, in Solo, December 17, 2014, in this photo taken by Antara Foto. The landslide in Banjarnegara destroyed a village and killed at least 32 people, according to officials. (Photo by Andika Betha/Reuters/Antara Foto)

A homeless man wearing face masks to protect against coronavirus, waits to receive basic medial help from members of a group of volunteer doctors of the Dom Druzei (Home of Friends) NGO in Moscow, Russia, Wednesday, April 1, 2020. As Moscow goes into lockdown amid the coronavirus pandemic, thousands of homeless people have trouble receiving food, water and shelter as Russia's capital closes non-essential businesses, cafes and parks. (Photo by Pavel Golovkin/AP Photo)

A worker disinfects a mosque for coronavirus, in Peshawar, Pakistan, Thursday, April 2, 2020. The government imposed a nationwide lockdown to try to contain the outbreak of the virus. (Photo by Muhammad Sajjad/AP Photo)

Protesters march against the death in Minneapolis police custody of George Floyd, in the Manhattan borough of New York City, U.S., June 1, 2020. (Photo by Mike Segar/Reuters)

Skeletons are arranged in a bar scene as part of a competition to create Day of the Dead altars on pedestrian Regina Street in central Mexico City, Tuesday, November 1, 2016. The holiday honors the dead as friends and families gather in cemeteries to decorate their loved ones' graves and hold vigil through the night on Nov. 1 and 2. (Photo by Rebecca Blackwell/AP Photo)

A model walks the runway during the BLACK TAPE PROJECT show at New York Fashion Week Powered By Art Hearts Fashion at The Angel Orensanz Foundation on September 9, 2018 in New York City. (Photo by Arun Nevader/Getty Images for Art Hearts Fashion)