Mystical Forest. Tracey Jennings photographed this seven-gill shark in a kelp forest just off the shore of Simon's Town near Cape Town, South Africa. You don't need to travel far from cities to visit Narnia. This 7 gill shark was photographed in a kelp forest just off the shore of Simonstown near Cape Town, South Africa. (Photo by Tracey Jennings/National Geographic Travel Photographer of the Year Contest)

“Winter Climbing from inside Ben Nevis”. The view from inside the mountain, as a winter climber passes through the cave on Minus Three gully. Photo location: Ben Nevis, Fort William, Scotland. (Photo and caption by Daniel Wildey/National Geographic Photo Contest)

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)

Private Wallace Tratford arrives home on leave, Drouin, Victoria, ca. 1944. A.I.F. Private Wallace Tratford, son of 1st Constable James Tratford, Drouin's only policeman (responsible for area of 105 square miles; 3,000 people), arrives home on his first leave from New Guinea battlefronts since he was married.

Katie Francis, a member of the Difficult Access Team from Wiss, Janney, Elstner Associates, inspects a gargoyle while rapelling down one of the north tower on the west front of the National Cathedral while looking for damage from August's magnitude 5.8 earthquake and high winds from Hurricane Irene October 17, 2011 in Washington, DC. DAT members used cameras, cell phones and iPad computers to record places on the cathedral's west front where damage was apparent. (Photo by Chip Somodevilla/Getty Images)

Dancers of the English National Ballet perform The Nutcracker at the Coliseum on December 14, 2011 in London, England. (Photo by Ian Gavan/Getty Images)

Ukrainian Air Force officers attend a graduation ceremony at the National University of Defence of Ukraine in Kiev, April 24, 2015. (Photo by Gleb Garanich/Reuters)

“Himalayan Dog”. This dog just appeared out of nowhere and followed us for an entire week during our trekking trip in the Himalayan outback. He always used to sleep in front of our tent and guarded us in the nights. When I decided to get up at 4 a.m. to climb the next 5000 m peak for sunrise he accompanied me as well. On the top he was sitting for the entire 30 minutes on this place looking straight into the countryside. Photo location: Ladakh, India. (Photo and caption by Sebastian Wahlhuetter/National Geographic Photo Contest)