The car driven by Scott Dixon, of New Zealand, goes over the top of Jay Howard, of England, in the first turn during the running of the Indianapolis 500 auto race at Indianapolis Motor Speedway, Sunday, May 28, 2017, in Indianapolis. (Photo by Marty Seppala/AP Photo)

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)

A model poses at Checkpoint Charlie, a historic place in the German capital to promote the fashion magazine “Sous” on June 12, 2012. (Photo by Maurizio Gambarini)

An Afghan National Army (ANA) soldier assigned to the Mobile Strike Force Kandak fires a RPG-7 rocket-propelled grenade launcher during a live-fire exercise supervised by the Marines with the Mobile Strike Force Advisor Team on Camp Shorabak, Helmand province, Afghanistan, May 20, 2013. The Marines with the Mobile Strike Force Advisor Team instructed and mentored their ANA counterparts on how to properly utilize their weapons systems. (Photo by SSgt Ezekiel R. Kitandwe/RCT 7)

“Strike Through The Mothership”. Every May for the last 3 years I have driven down to Tornado Alley to capture some amazing storms. This supercell held so much promise to drop a tornado but one small shift in the atmosphere and all that it produced was an extreme lightning show. Photo location: Broken Bow, Nebraska. (Photo and caption by Vanessa Neufeld/National Geographic Photo Contest)

Men stroll past roadside vendors as a painted truck makes its way through the busy street in Kabul, Afghanistan, November, 1961. (Photo by Henry S. Bradsher/AP Photo via The Atlantic)

Meet the world's smoothest cuddliest hedgehog. Names after brave hero, but Nelson is completely bald so when curled up he looks like an egg. Doesn't have a single prickle or strand of hair. Thought to be suffering a stress related alopecia following a trauma in the wild. Volunteers have been massaging him for half an hour a day for the last year to encourage spikes to grow. Now given up but he still gets daily massages because he enjoys them so much and to keep his cuddle skin soft and smooth. Unlike his namesake Nelson could not defend himself so will live out his days at the Foxy Lodge Wildlife Rescue in Hemsby, England. (Photo by Jeremy Durkin)

A man dressed as the Sesame Street character Big Bird sits on a bench waiting to take pictures with people walking through Central Park in New York U.S., November 14, 2016. (Photo by Shannon Stapleton/Reuters)