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)

An Indian Sikh Nihang, or warrior, performs Gatka martial arts skills during a procession at the Golden Temple in Amritsar on January 6, 2014, as part of birth anniversary celebrations of Guru Gobind Singh. The birth anniversary of Guru Gobind Singh, the tenth Sikh guru, is marked on January 6. (Photo by Narinder Nanu/AFP Photo)

Nine year old girl Barsati reacts while walking on a tightrope in Mumbai on February 11, 2014. Barsati, and her younger brother Rajababu, (4) earn an average of around 2000 rupees (32 dollars) per day from pedestrians and tourists performing various acts on the tightrope near the city's iconic landmark Gateway of India. (Photo by Indranil Mukherjee/AFP Photo)

“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)

“Magician David Blaine's latest stunt boasts lots of high-voltage snap, crackle and pop – but experts say he'll be safe from electrocution as long as he wears his chain-mail suit and metal headgear”. – NBC News. Photo: Blaine stands inside the apparatus, surrounded by a million volts of electric currents streamed by tesla coils. The stunt, sponsored by Intel, is the latest of daredevil endeavors by the magician whose previous stunts included being encased in ice for over 60 hours in Times Square, on October 5, 2012. (Photo by John Minchillo/Associated Press)

In this Tuesday, March 31, 2015 photo, Indian women walk carrying firewood they collected from a forest at Gobhali village on the outskirts of Gauhati, India. Every evening, hundreds of millions of Indian women hover over crude stoves making dinner for their families. They feed the flames with polluting fuels like kerosene or cow dung, and breathe the acrid smoke wafting from the fires. (Photo by Anupam Nath/AP Photo)

Soniya, 6, whose family moved to Islamabad from Pakistan's Khyber-Pakhtunkhwa province to look for work, stands outside their house on the outskirts of Islamabad January 1, 2015. (Photo by Zohra Bensemra/Reuters)

A devotee carrying an idol of the Hindu god Ganesh, the deity of prosperity, jumps into the Sabarmati river to immerse the idol during the 10-day-long Ganesh Chaturthi festival in Ahmedabad, India, September 11, 2016. (Photo by Amit Dave/Reuters)