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 woman lies injured after an incident on Westminster Bridge in London on Wednesday, March 22, 2017. A police officer has been stabbed near to the British Parliament and the alleged assailant shot by armed police. Scotland Yard report they have been called to an incident on Westminster Bridge where several people have been injured by a car. (Photo by Toby Melville/Reuters)

In this photo taken with long time exposure, a woman wears a hat at Churchill Downs before the 145th running of the Kentucky Derby horse race Saturday, May 4, 2019, in Louisville, Ky. (Photo by Charlie Riedel/AP Photo)

Eagle Prime (MK3), a giant robot by MegaBots Inc. which manufactures giant piloted humanoid fighting robots headquartered in Berkeley, California on October 18, 2017. (Photo by Courtesy Michael Mauldin/Reuters/MegaBots Inc)

An Indonesian woman watches an eruption from the Mount Sinabung volcano from Tiga Pancur village, in Karo in North Sumatra on November 3, 2017. Sinabung roared back to life in 2010 for the first time in 400 years. After another period of inactivity it erupted once more in 2013, and has remained highly active since. (Photo by Ivan Damanik/AFP Photo)

Iraqi firefighters try to stop the fire of burning oil wells in Kirkuk, northern Iraq, 02 June 2016. Two Khabbaz oil field wells in Kirkuk Province, northern Iraq, exploded by suspected insurgents, a security official said. (Photo by EPA/Stringer)

French-Argentine actress Berenice Bejo poses during a photocall for “Final Cut (Coupez !)” at the 75th edition of the Cannes Film Festival in Cannes, southern France, on May 18, 2022. (Photo by Loic Venance/AFP Photo)

Alejandro Ccasa prays after waiting three days next to an empty oxygen tank for his uncle who has COVID-19 outside a refill shop where he is the first in line before it opens in Callao, Peru, early Tuesday, February 2, 2021. Ccasa said his family has one large tank and it gives about four hours of oxygen therapy. (Photo by Martin Mejia/AP Photo)