“Mr Big Dipper”, Nicholas Roemmelt (Denmark). A stargazer observes the constellation of the Big Dipper perfectly aligned with the window of the entrance to a large glacier cave in Engadin, Switzerland. This is a panorama of two pictures, and each is a stack of another two pictures: one for the stars and another one for the foreground, but with no composing or time blending. (Photo by Nicholas Roemmelt/National Maritime Museum/The Guardian)

Two women wearing nun outfits drink beer while watching the 2014 Tim Hortons Brier curling championships in Kamloops, British Columbia in this March 8, 2014 file photo. Although some people might conclude that a curling event could produce a dull atmosphere, it is actually far from it. Some of the most energetic and loyal fans are committed to showing their colours at tournaments around the world. There was a lull in the games that were being held on this day and I remember spotting these nuns sitting in their seats earlier. Although them just sitting there didn't produce a picture, I kept my eye on them for the entire match. As soon as I spotted them with beer in their hands, I slowly turned my camera towards them and waited for them to take a drink. One of the challenges of shooting this image was to not have everyone notice me taking the photo. I had a longer lens on and was right in the middle of the rink. I slowly turned my lens, not to make my intentions too obvious, and waited until they drank from their beers together. (Photo and caption by Ben Nelms/Reuters)

People take a selfie at the abandoned former Soviet R12 nuclear missile launch site in Zeltini, Latvia, July 22, 2016. Hidden in the forests of Aluksne, near Latvia's north-eastern border with Russia, the remains of a former Soviet nuclear missile base are a magnet for tourists now rather than a top-secret site manned by soldiers. (Photo by Ints Kalnins/Reuters)

“Fly cap for a vine snake”. A fly lands on the head of a vine snake in the Choco of Colombia. (Photo and caption by Robin Moore/National Geographic Traveler Photo Contest)

ATTENTION! All pictures are presented in high resolution. To see Hi-Res images – just TWICE click on any picture. In other words, click small picture – opens the BIG picture. Click BIG picture – opens VERY BIG picture.

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 worker applies colour to strings which will be used to fly kites, by a roadside in Ahmedabad, India, November 23, 2017. (Photo by Amit Dave/Reuters)

«Little Red Riding Hood». “The moment I pulled this sweater out of the drawer for Frankie I knew what I wanted for my picture today. I envisioned the look, the style, and the composition. When working with a 2 year old it is never easy to actually get the shot you want, especially when they decide to skip nap time. But I really like how this one turned out” – Rich. (Photo by Rich)

Merit Prize Winner: “A Well Earned Rest in the Sahara”. This photo of Moussa Macher, our Tuareg guide, was taken at the summit of Tin-Merzouga, the largest dune (or erg) in the Tadrat region of the Sahara desert in southern Algeria. Moussa rested while waiting for us to finish our 45-minute struggle to the top. It only took ten minutes of rolling, running, and jumping to get back down. The Tadrat is part of the Tassili N'Ajjer National Park World Heritage area, famous for its red sand and engravings and rock paintings of cattle, elephants, giraffes, and rhinos that lived there when the climate was milder. Photo location: Summit of Tin-Merzouga, Tadrat, Tassili N'Ajjer National Park, Algeria. (Photo and caption by Evan Cole/National Geographic Photo Contest)