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)

British prime minister Winston Churchill (1874–1965) stops to pet a cat at Liverpool Street Station, 24th May 1952. (Photo by Keystone/Hulton Archive/Getty Images)

Sara Sampaio attends “The Killing Of A Sacred Deer” screening during the 70th annual Cannes Film Festival at Palais des Festivals on May 22, 2017 in Cannes, France. (Photo by David Fisher/Rex Features/Shutterstock)

Republican Presidential Candidate Donald Trump kisses his wife Melania Trump as he introduces her during first day of the Republican National Convention in Cleveland, Monday, July 18, 2016. (Photo by Matt Rourke/AP Photo)

The double compound eyes of a male St. Mark's fly (Bibio marci), submitted by Dr. David Maitland from Feltwell, UK. (Dr. David Maitland)

A British Army Rolls Royce armoured car outside the Royal Ulster Constabulary police station on York Street in Belfast following riots after an Orange Order parade. (Photo by Fox Photos/Getty Images). 20th June 1935

Model Bella Hadid celebrates her 20th birthday with her mother Yolanda Foster, The Weeknd and Shanina Shaik at Up & Down in New York City, NY on October 10, 2016. (Photo by TheStewartofNY/Splash News)

Nick Franklin, in action during the FMX competition at the 23rd edition of Free4Style this Saturday, July 2, 2016 in Estavayer-le-Lac,Switzerland. (Photo by Jean-Christophe Bott/Keystone/APA)