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)

The X-47B prototype on Tuesday flew off an aircraft carrier and into the history books. Today's achievement, the first-ever catapult launch of an unmanned aircraft from the flight deck of a carrier, promises to open up a new chapter in the annals of naval aviation. Photo: An X-47B pilot-less drone combat aircraft is launched for the first time off an aircraft carrier, the USS George H. W. Bush, in the Atlantic Ocean off the coast of Virginia, May 14, 2013. The U.S. Navy made aviation history on Tuesday by catapulting an unmanned jet off an aircraft carrier for the first time, testing a long-range, stealthy, bat-winged plane that represents a jump forward in drone technology. (Photo by Jason Reed/Reuters)

Motocross riders compete on the beach on October 15, 2023 in Weymouth, United Kingdom. The motocross event, which first came to the town in 1984, organised by Weymouth and Portland Lions Club in association with Purbeck Motocross Club, sees over 300 riders compete over a course along Weymouth beach. (Photo by Finnbarr Webster/Getty Images)

Drag queens Maude Boate, Anita Wiglit and Kita Mean pose for a photograph before boarding the NSW TrainLink Silver City Stiletto train at Central station in Sydney, Australia, 12 September 2019. Drag queens and kings will travel to the outback NSW town of Broken Hill to attend the annual Broken Heel festival, paying homage to the iconic Australian film “Priscilla, Queen of the Desert”. (Photo by James Gourley/AAP)

Chinese tourists watch storm clouds moving along the coast towards the city of Sydney, Australia, November 6, 2015. Powerful storms swept across the city on Friday, with the Australian Bureau of Meteorology issuing a warning for severe thunderstorms with large hailstones, heavy rainfall and damaging winds, local media reported. (Photo by David Gray/Reuters)

A woman stumbes as people run down Oxford Street, London, Britain, November 24, 2017. Police are responding to reports of an incident at London's Oxford Circus Tube station and have urged the public to avoid the area. (Photo by Peter Nicholls/Reuters)

The second annual Salon du Chocolat exhibition and fashion show at LeGourmet in Galeries Lafayette, Dubai Mall on May 18, 2023. Dress “Madonna” created by Chef Christiane S. Trilck designed by Julian Knips. (Photo by Antonie Robertson/The National)

A security guard walks past a giant Doctor Who poster at the “Doctor Who 50th Celebration” event in the ExCeL centre on November 22, 2013 in London, England. The sold-out three day event in the ExCeL London convention centre celebrates 50 years of the show which has seen 11 actors play the role of Doctor Who and receives a worldwide cult following. (Photo by Oli Scarff/Getty Images)