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 rider on horseback competes in the Margalla Festival Tent Pegging Championship in Islamabad, Pakistan, June 5, 2016. Tent pegging is an equestrian sport popular in India and Pakistan, with a history going back to the cavalries of ancient armies. (Photo by Caren Firouz/Reuters)

A woman wears a flower crown during a Summer Solstice celebration on June 21, 2021 in Krakow, Poland. The summer solstice represents the longest day of the year, with the most hours of sunlight, and is celebrated by various cultures worldwide. (Photo by Omar Marques/Getty Images)

A woman dressed in an alien space suit carries an American flag and a sign that reads “Women's Revolution 1971” as she marches in a Women's Liberation demonstration on Fifth Avenue in New York, August 26, 1971. (Photo by Marty Lederhandler/AP Photo)

A street merchant waits for customers in Niamey, Niger, Monday, August 14, 2023. Niger's mutinous soldiers say they will prosecute deposed President Mohamed Bazoum for “high treason” and undermining state security. (Photo by Sam Mednick/AP Photo)

A tourist train is decorated with Christmas lights in Bogotá, Colombia on December 10, 2017. (Photo by Jaime Saldarriaga/Reuters)

A woman uses a plastic bad to protect her head amid snowfall in Beijing, China on December 14, 2023. (Photo by Tingshu Wang/Reuters)

This handout picture released by Jordan's Aqaba Special Economic Zone Authority (ASEZA) on July 23, 2019 shows a Jordanian Armed Forces armored vehicle lies on the seabed of the Red Sea off the coast of the southern port city of Aqaba, part of a new underwater military museum. (Photo by Aqaba Special Economic Zone Authority via Reuters)