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)

Genko Stoykov fires a rifle as he and other men prepare for the traditional “Horo” dance on Epiphany Day in the icy winter waters of the Tundzha river on January 6, 2022 in Kalofer, Bulgaria. As part of the tradition, a priest throws a cross in the river and it is believed that the one who retrieves it will be healthy throughout the year. Today, cultures throughout Christendom mark the Feast of the Epiphany, when Jesus was revealed to the Magi as God incarnate. (Photo by Hristo Rusev/Getty Images)

Revellers at the Chin Chin music festival in Amsterdam, Netherlands on July 3, 2021. The festival season has started with a QR code, one can enter, corona proof or vaccination proof in the corona check app. (Photo by Robin Utrecht/Rex Features/Shutterstock)

Children play football on March 10, 2022 on a concrete slab in Mukuru Kwa Njenga informal settlements, where structures have been demolished in November 2021 to pave the way for the construction of the Nairobi Expressway. (Photo by Simón Maina/AFP Photo)

Britney Spears supporter Phoebe Price and her dog Henry take pictures next to a “Free Britney” Christmas tree set by fans outside a hearing concerning the pop singer's conservatorship at the Stanley Mosk Courthouse, Friday, November 12, 2021, in Los Angeles. A Los Angeles judge ended the conservatorship that has controlled Spears' life and money for nearly 14 years. (Photo by Damian Dovarganes/AP Photo)

Marines of the Baltic Fleet forces of the Russian Navy train in the zone of obstacles during military exercises at the Khmelevka firing ground in the Kaliningrad region, Russia on November 24, 2021. (Photo by Vitaly Nevar/Reuters)

China's Shang Chunsong prepares to compete in the uneven bars event of the women's individual all-around final artistic gymnastics competition at the Namdong Gymnasium Club during the 17th Asian Games in Incheon, in this September 23, 2014 file photo. (Photo by Kim Hong-Ji/Reuters)

A couple kiss in front of a barricade set by demonstrators during clashes with police following a protest condemning the arrest of rap singer Pablo Hasél in Barcelona, Spain, Thursday, February 18, 2021. Protests over the imprisonment of a rapper convicted for insulting the Spanish monarchy and praising terrorist violence have morphed for the third night in a row into rioting. Pablo Hasél began this week to serve a 9-month sentence in a northeastern prison. (Photo by Emilio Morenatti/AP Photo)