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)

Framed by the setting sun, an American Bison grazes at the Tallgrass Prairie National Preserve on Tuesday, April 28, 2015, near Strong City, Kan. The buffalo herd at Tallgrass is one of the few herds of wild bison left in the United States. (Photo by Travis Heying/The Wichita Eagle via AP Photo)

A child plays with a soap bubble on the city hall plaza on March 14, 2015 in Paris. (Photo by Dominique Faget/AFP Photo)

A woman plays billiards during a local championship at a sports hall in Yemen's capital Sanaa on December 16, 2019. (Photo by Mohammed Huwais/AFP Photo)

Icelandic horses play on a stud farm in Wehrheim Frankfurt, Germany, as the sun rises on Thursday, May 21, 2020. (Photo by Michael Probst/AP Photo)

The Sheep watch the sunset from the top of Cleeve Hill, Cheltenham, United Kingdom on June 22, 2020. (Photo by Jack Boskett/The Telegraph)

Commuters wearing face masks jostle for a ride on a bus discarding social distancing guidelines in Kolkata, India, Tuesday, July 21, 2020. With a surge in coronavirus cases in the past few weeks, state governments in India have been ordering focused lockdowns in high-risk areas to slow down the spread of infections. (Photo by Bikas Das/AP Photo)

A devotee of Hindu goddess Kali performs a ritual during the “Bonalu” festival in Hyderabad, India, Sunday, July 28, 2019. Bonalu is a month-long Hindu folk festival of the Telangana region dedicated to Kali, the Hindu goddess of destruction. (Photo by Mahesh Kumar A./AP Photo)