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)

People ride a prototype of a driverless vehicle as it is moves through a pedestrian area in Greenwich, east London, February 11, 2015. Britain has begun testing driverless cars in four cities, launching the first official trials ahead of a series of planned rule reviews to accommodate the new technology. (Photo by Suzanne Plunkett/Reuters)

A BASE jumper is pictured against the skyline shrouded in a thick haze during the Kuala Lumpur Tower International Jump in Kuala Lumpur, Malaysia, 02 October 2015. More than 100 BASE jumpers take part in this extreme sport event, which enters its 15th year. The haze hovering over Malaysia is caused by the ongoing plantation and forest fires in the nearby Indonesian provinces of Sumatra and Kalimantan. (Photo by Fazry Ismail/EPA)

A jockey falls off during a traditional Barapan Kebo or buffalo races, in Taliwang, on the island of Sumbawa, West Nusa Tenggara, Indonesia November 22, 2015. Around 250 pairs of water buffalo took part in the Barapan Kebo ahead of the planting season, for prizes which included a top prize of a pilgrimage to Mecca. (Photo by Sigit Pamungkas/Reuters)

“Elat’ma, the Ryazan Oblast region of Russia. This small town is only 300 kilometers (186 miles) from modern Moscow but remains 60 years in the past, dominated by the spirit of socialism. The air of the communist ‘50s can be seen in the town’s architecture, celebrations and other occurrences. But neither its beauty nor its ties to a socialist past brought photographer Anastasia Rudenko to this village. Elat’ma is unique in that it functions as a town for mentally disabled people”. – Michelle Cohan via CNN. (Photo by Anastasia Rudenko)

Papai Simon Ole Mamai of the Maasai Cricket Warriors team from Kenya runs during a match against English team “The Shed” during “The Last Man Stands” cricket tournament at Dulwich sports ground in South London September 1, 2013. (Photo by Philip Brown/Reuters)

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A woman smokes marijuana during the annual 4/20 marijuana rally on Parliament Hill in Ottawa, Ontario, Canada, April 20, 2017. (Photo by Chris Wattie/Reuters)