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 Fulton Hotshot lights a controlled burn on the so-called “Rough Fire” in the Sequoia National Forest, California, August 21, 2015. In California, suffering its worst drought on record, about 2,500 people were forced to flee Christian camps east of Fresno at Hume Lake as the so-called Rough Fire crossed Highway 180, officials said. (Photo by Max Whittaker/Reuters)

“By 1969, the fashion choices of tens of millions of young American men and women were as variegated and ever-evolving as the world around them. Cultural transformation was an irresistible force during the Sixties, and across America and around the globe civil rights, women’s and gay liberation, the sexual revolution and, of course, the explosive soundtrack of R&B, soul and rock and roll informed everything from politics to fashion”. – LIFE. Photo: Corona del Mar High School students Kim Robertson, Pat Auvenshine and Pam Pepin wear “hippie” fashions, 1969. (Photo by Arthur Schatz/Time & Life Pictures)

The photography of Art Wolfe covers the globe, capturing landscapes, wildlife, and cultures from every continent; here he talks through a selection of his favourite images. Art Wolfe is an American photographer and conservationist. His photographs have been noted by environmental advocacy groups for their “stunning” visual impact. Here: Snowy owlets (Bubo scandiacus), Arctic National Wildlife Refuge, Alaska, USA. (Photo by Art Wolfe/Art Wolfe Stock)

In this photo taken on Friday, July 14, 2017, a student at a paramilitary camp for children calls the rank to attention outside Kiev, Ukraine. As the deadly conflict in eastern Ukraine entered its third year, some parents in Ukraine are anxious to make sure their children are ready to fight it, instead of swimming and playing volleyball. (Photo by Efrem Lukatsky/AP Photo)

Despite the mild 14°С shoppers and commuters battle against the wind and rain on Waterloo Bridge, London on December 28, 2022. (Photo by Alex Lentati/London News Pictures)

People drink in the street in the Soho area of London, on April 12, 2021 as coronavirus restrictions are eased across the country in step two of the government's roadmap out of England's third national lockdown. Britons on Monday toasted a significant easing of coronavirus restrictions, with early morning pints – and much-needed haircuts – as the country took a tentative step towards the resumption of normal life. Businesses including non-essential retail, gyms, salons and outdoor hospitality were all able to open for the first time in months in the second step of the government's roadmap out of lockdown. (Photo by Tolga Akmen/AFP Photo)

A Palestinian girl wear a face mask during a lockdown imposed following the discovery of coronavirus cases in the Gaza Strip, Thursday, August 27, 2020. On Wednesday Gaza's Hamas rulers extended a full lockdown in the Palestinian enclave for three more days as coronavirus cases climbed after the detection this week of the first community transmissions of the virus in the densely populated, blockaded territory. (Photo by Hatem Moussa/AP Photo)