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)

Ukrainians wearing traditional costumes sing Kolyadky or Ukrainian Christmas Carols, as a part of Orthodox Christmas in Kiev, Ukraine, Thursday, January 7 2016. Orthodox Christians mark their traditional Christmas Day Jan. 7, with many ancient symbolic events. (Photo by Sergei Chuzavkov/AP Photo)

A man walks though Times Square in high heels during unseasonably warm weather on Christmas Eve in the Manhattan borough of New York December 24, 2015. (Photo by Carlo Allegri/Reuters)

Residents watch volcanic smoking and ashes rising from Mount Sinabung during an eruption in Karo, North Sumatra, Indonesia, February 24, 2016. Authorities have repeatedly called on local residents to remain patient in dealing with the impact of Sinabung's eruptions, which some experts have predicted will continue for five more years. (Photo by Xinhua/Barcroft Media)

Train attendants take part in a parade training as they visit the national flag guard during a patriotic education event ahead of the 90th anniversary of the founding of the Chinese People's Liberation Army (PLA) in Beijing, China July 25, 2017. (Photo by Reuters/China Stringer Network)

Nicole Scherzinger at the “The X Factor” TV show, Series 14, Episode 15, Judges' Houses in Sun City, South Africa on October 21, 2017. (Photo by Dymond/Thames/Syco/Rex Features/Shutterstock)

Lush green rice terraces sprawl over 2,200 hectares of mountainside ready to be harvested. These stunning images, captured by photographer Saravut Whanset, show the incredible terraces throughout the course of the day, including at sunrise and sunset. Workers tend to the fields, with each terrace between 1 and 1.5 metres wide, while wooden huts stand on stilts on the mountainside. The beautiful panoramic pictures were taken in Mu Cang Chai, Vietnam, with the fields located at the foot of the Hoang Lien Son mountain range, 1,000 metres above sea level. (Photo by Saravut Whanset/Solent News and Photo Agency)

Marine biologist Simon Pierce, who studies whale sharks, happened to be in the right place at the right time to capture amazing photo off Cancun, Mexico. (Photo by Simon Pierce/Mercury Press/Caters News)