Women carry gas cylinders to fill them at a distribution point in Cairo January 19, 2015. Egypt is going through its worst energy crisis in decades and is seeking fresh sources of natural gas, which powers most of its homes and factories. (Photo by Mohamed Abd El Ghany/Reuters)

David Hall’s photographs of scenery and creatures off the coast of Canada in the Pacific Northwest portray serenity under the water, which belie the extreme challenges he faces to get his images. For each shoot, Hall wears a dry suit, a neoprene body suit that covers all of his body but his head and traps air inside to keep him warm. Water temperature in Canada’s British Columbia typically ranges between 45 and 50 degrees Fahrenheit. Photo: Moon jellyfish and cross jellies. (Photo by David Hall)

“Asaro from the Eastern Highlands”. The mudmen could not cover their faces with mud because the people of Papua New Guinea thought that the mud from the Asaro river was poisonous. So instead of covering their faces with this alleged poison, they made masks from pebbles that they heated and water from the waterfall, with unusual designs such as long or very short ears either going down to the chin or sticking up at the top, long joined eyebrows attached to the top of the ears, horns and sideways mouths. (Photo and caption by Jimmy Nelson)

The X-47B prototype on Tuesday flew off an aircraft carrier and into the history books. Today's achievement, the first-ever catapult launch of an unmanned aircraft from the flight deck of a carrier, promises to open up a new chapter in the annals of naval aviation. Photo: An X-47B pilot-less drone combat aircraft is launched for the first time off an aircraft carrier, the USS George H. W. Bush, in the Atlantic Ocean off the coast of Virginia, May 14, 2013. The U.S. Navy made aviation history on Tuesday by catapulting an unmanned jet off an aircraft carrier for the first time, testing a long-range, stealthy, bat-winged plane that represents a jump forward in drone technology. (Photo by Jason Reed/Reuters)

“Are you here for the Winery Tour?” This is a Western Grey Kangaroo caught lounging in the wineries of the Adelaide Hills in South Australia. This past Autumn has been a spectacular time for wildlife viewing and I got lucky to spot this guy while mountain biking in the hills. Such a funny stance it just begs the question... Have you been drinking? ...and or... Are you here for the Winery Tour? Such a spontaneous moment I figured it would be perfect for an entry. I hope you like it! Cheers. Photo location: Adelaide Hills, South Australia, Australia. (Photo and caption by Greg Snell/National Geographic Photo Contest)

“The Falles is a traditional celebration held in commemoration of Saint Joseph in Valencia, Spain. The term Falles refers to both the celebration and the monuments created during the celebration. A number of towns in the Valencian Community have similar celebrations inspired by the original in Valencia”. – Wikipedia

Photo: A person prepares for the burning of the “Ninot” caricatures during the last day of the “Fallas” festival on March 19, 2012 in Valencia, Spain. The festival, which runs March 15 – 19, celebrates the arrival of spring with fireworks, fiestas and bonfires. (Photo by Xaume Olleros/Getty Images)

The Euro sculpture is partially reflected in a puddle on a cobblestone pavement in front of the headquarters of the European Central Bank in Frankfurt on Jan. 21. (Kai Pfaffenbach/Reuters)

Frog legs it! Indonesian flying frog tries to hitch a ride on snail's back before realising it would be quicker to hop it alone. A tiny frog struck up an unlikely friendship with a giant African land snail after clambering onto its shell to catch a ride. (Photo by Hendy Mp/SOLENT/Visual Press Agency)