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 young Chinese girl kicks during a kung-fu class at Ritan Park on June 11, 2016 in Beijing, China. Ritan, meaning “sun altar”, is among the oldest parks in Beijing, built in the early 1500s during the Ming dynasty for the emperor to make sacrifices to the sun. (Photo by Kevin Frayer/Getty Images)

Police detain Sebahat Tuncel, co-chair of the pro-Kurdish Democratic Regions Party (DBP), during a protest against the arrest of Kurdish lawmakers, in the southeastern city of Diyarbakir, Turkey, November 4, 2016. (Photo by Sertac Kayar/Reuters)

Participants take part in a high-heel race at a Gay Pride party in the central neighborhood of Chueca in Madrid on July 3, 2014. (Photo by Gerard Julien/AFP Photo)

A male sea lion Leo writes the word of tiger in Chinese character at a New Year's attraction to celebrate the Year of the Tiger at the Hakkeijima Sea Paradise aquarium in Yokohama, suburban Tokyo on Monday, January 3, 2022. The calligraphy attraction by the sea lion will be carried through January 31. (Photo by Yoshio Tsunoda/AFLO/Rex Features/Shutterstock)

In this June 20, 2015 photo, Niberta Galvez uses the bottom half of his shirt to collect coca leaves in Samugari, Peru. Coca farmers were among the locals who, in 1984, formed citizen militias to help the military beat back Shining Path rebels, reducing them to a small group of fewer than 500 who now are deeply involved in drug trafficking. (Photo by Rodrigo Abd/AP Photo)

British actress Elizabeth Hurley poses for photographers during a beachside event to promote her swimwear range in Cannes, France on May 23, 2006. (Photo by Michel Dufour/WireImage)

UK Love Island beauty Samira Mighty (L) seen arriving at Mahiki Kensington on November 16, 2018 in London, England. (Photo by CURLEY)