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)

A member of the “Castellers Minyons de Terrassa” adjusts her belt before forming a human tower or ÒcastellÓ during the festival of the patron saint of Barcelona “The Virgin of Mercy” at Sant Jaume square in Barcelona, Spain, September 20, 2015. The formation of human towers is a tradition in Catalonia dating back to the 18th century. (Photo by Susana Vera/Reuters)

The Lumix GX1 single lens reflex (SLR) camera with 14-42 mm powerzoom lens is displayed at the Panasonic booth at the 2012 International Consumer Electronics Show at the Las Vegas Convention Center January 10, 2012 in Las Vegas, Nevada. The new camera comes with an external viewfinder and flash and an ISO up to 12,800. The camera as shown sells for USD 949; the camera body alone is USD 799. (Photo by Ethan Miller/Getty Images)

Spanish bullfighter Manuel Jesus “El Cid” is seen through a small window of a door as he performs a pass to a heifer during a “tentadero” (a small bullfight to check the bravery of calves and heifers which are not killed) during the first International Biennial of bullfighting at Reservatauro Ronda cattle ranch in Ronda, near Malaga February 17, 2013. Spain's parliament voted last Tuesday to consider protecting bullfighting as a national pastime, angering animal rights campaigners and politicians in two regions where the sport is banned. (Photo by Jon Nazca/Reuters)

Murad Khydyrov, horse and monkey trainer at the Great Moscow State Circus, and chimpanzee named Micky get ready for a rehearsal of the show called “History” as the circus prepares for its new season, which is to begin on September 19, in Moscow on September 17, 2020. (Photo by Natalia Kolesnikova/AFP Photo)

Dancers from “LA Dance Project” perform, wearing a mask, during the drive-in show “Solo at Dusk” in Los Angeles, California, on October 13, 2020, amid the Coronavirus pandemic. (Photo by Valerie Macon/AFP Photo)

Two young women pose for a portrait, dressed in robes after collecting their Bachelor degrees in Conakry on October 12, 2020. Presidential elections are to be held on October 18, with incumbent President bidding for a third term in office, defying critics who say he forced through a new constitution this year enabling him to sidestep two-term presidential limits. (Photo by John Wessels/AFP Photo)

Crowds on the beach in Cape Canaveral, Fla., watch the launch of the SpaceX Falcon 9 Crew Dragon on its Crew-1 mission carrying four astronauts, Sunday, November 15, 2020, in this 3 1/2-minute time exposure. The rocket was launched from Launch Complex 39A at Kennedy Space Center at 7:27 p.m. Sunday evening. (Photo by Malcolm Denemark/Florida Today via AP Photo)