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)

Russia's Maria Sharapova carries the torch during the opening ceremony of the 2014 Winter Olympics in Sochi, Russia, Friday, February 7, 2014. (Photo by Matt Dunham/Associated Press)

“The Tonight Show” host Jimmy Fallon, center, exits the water during the Chicago Polar Plunge, Sunday, March 2, 2014, in Chicago. Fallon joined Chicago Mayor Rahm Emanuel in the event. (Photo by Andrew A. Nelles/AP Photo)

Eurovision fans from Sweden kiss in front of the Globen Arena prior the first the Eurovision Song Contest final in Stockholm, Sweden, Saturday, May 14, 2016. (Photo by Martin Meissner/AP Photo)

In this Friday, February 1, 2019, photo, Filipino-Chinese display piggy banks at the start of celebrations leading to next week's Lunar New Year in Chinatown, Manila, Philippines. This year is the Year of the Earth Pig on the Lunar calendar and is supposed to represent abundance, diligence and generosity. (Photo by Bullit Marquez/AP Photo)

This image obtained January 31, 2017 from the US Geological Survey's Hawaiian Volcano Observatory showing a lava stream, pouring out of the lava tube on the sea cliff at the Kamokuna ocean entry from the Kilauea Volcano on January 29. (Photo by AFP Photo/USGS)

A worker fills a public bus with diesel as the bus driver and passengers look on, at a fuel station in Kolkata, India, February 1, 2017. (Photo by Rupak De Chowdhuri/Reuters)

Fighting Infections (single image) | Fighting Pandemic by Sudipto Das. “It’s exhausting. A tram conductor in Kolkata, India, wears protective clothing from head to toe even in the heat of a summer afternoon. This was when restrictions were easing after India’s first Covid-19 lockdown – public transport was running, but staff were advised to suit up like this. We’ve all grown used to saluting the efforts of healthcare workers, but plenty of other people in public-facing jobs have performed gruelling duties too to keep people safe”. (Photo by Sudipto Das/Wellcome Photography Prize 2021)