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)

Employee Victoria Livesey walks past Banksy's “Kate Moss 2005” on display at Bonhams on March 23, 2012 in London, England. The painting, estimated at GBP 30,000 – 50,000, USD 48,000 – 79,000 and 35,000 – 59,000 euros forms part of the Urban Art Sale, which takes place at Bonhams on March 29, 2012. (Photo by Peter Macdiarmid/Getty Images)

A girl broadcasts at live streaming talent agency Three Minute TV in Beijing, China on April 12, 2017. Three Minute TV also arranges cosmetic surgery at partner hospitals for its anchors, arranges small bank loans for the surgery, photographs and markets the anchors and helps them find acting opportunities Deng said. (Photo by Damir Sagolj/Reuters)

A vegetarian festival devotee gets medical attention after a parade at Jui Tui shrine on September 30, 2014 in Phuket, Thailand. (Photo by Borja Sanchez-Trillo/Getty Images)

A students with her face smeared in coloured powder, celebrates Holi at a university campus in Chandigarh, India March 23, 2016. (Photo by Ajay Verma/Reuters)

The festival marks the end of the monsoon season and beginning of autumn. More than hundred girls under the age of nine gathered for the tradition of worshiping young pre-pubescent girls as manifestations of the divine female energy. The ritual holds a strong religious significance in Newar community. It is a community affair held primarily to save small girls from diseases and bad luck in the years to come. Photo: A young Nepalese girl dressed as a Kumari or living Goddess, smiles for camera as she waits for Kumari puja at Hanuman Dhoka, Basantapur Durbar Square in Katmandu, Nepal, Tuesday, September 17, 2013. (Photo by Niranjan Shrestha/AP Photo)

Only 156 people remained in the tribe when Jan visited in Accham District, Nepal, January 2016. Hidden deep in the Himalayan forest is one of the world’s last enduring nomadic tribes who are resisting attempts to move them into permanent settlements. (Photo by Jan Moller Hansen/Barcroft Images)