National Geographic has created “Air, Land & Sea: the 50 greatest wildlife photographs” exhibition. Here: CT4 Crocodile cave on the Salamat river. Set up with Nathan Williamson last chip rain came while we were with the nomads. (Photo by Michael Nichols/National Geographic)

Indonesian rescuers search for victims of the crashed military airplane in Medan, North Sumatra, Indonesia, 30 June 2015. At least people 49 people were killed after an Indonesian military plane crashed in North Sumatra and burst into flames, officials said. Air Force chief Air Marshal Agus Supriatna said there were no survivors after the plane ploughed into houses and commercial buildings in Medan, the country's third largest city. The plane left Jakarta with 113 people aboard, including military personnel and their relatives, but it was not clear how many continued the journey to Medan after stopovers in Pekanbaru and Dumai, Agus said. (Photo by Dedi Sahputra/EPA)

On Earth Day this year, NASA asked people all around the world a question: “Where are you on Earth Right Now?” To answer this question people were asked to post their selfie on social media. The goal was to use each picture as a pixel in the creation of a “Global Selfie” – a mosaic image that would look like Earth appeared from the space. The 3.2 gigapixel “Global Selfie”, was made the with 36,422 individual images.

This photo of an elephant seal and Gentoo penguin shot by Andrew James in Yankee Harbour, Antarctica. (Photo by Andrew James/Travel Photographer of the Year)

A dog jumps into a swimming pool to retrieve a ball during the Chatsworth House Country Fair near Edensor, Britain on August 31, 2018. (Photo by Darren Staples/Reuters)

Here are the bravest of the brave in 2016. Weve gathered some of the finest images showing daredevils taking their lives into their own hands and going to the very brink this year. Whether they are perched hundreds of feet up on a high wire, courageously clinging to a rockface or taking on a volcano, these adventurers take the breath away. Here: Morgane Choquet and Samuel Cobb relax in a vertical campsite on the slopes of El Capitan, Yosemite National Park. (Photo by Alexandre Eggermont/Caters News)

Drastic inequality is by no means new in New York. Jacob A. Riis was called a muckraker after he chose to spotlight the city’s poverty at the turn of the 20th century by photographing it. Here: Sweatshop in Hester Street, 1889-1890. (Photo by Jacob A. Riis/Museum of the City of New York, Gift of Roger William Riis)

“Serengeti National Park encompasses 5,700 square miles of grassy plains and woodlands near the northern border of Tanzania, and is home to more than 3,500 lions grouped into a couple dozen prides. Photographer Nick Nichols and videographer Nathan Williamson made several extended trips to the Serengeti between July 2011 and January 2013, determined to break new visual ground in their coverage of the Serengeti Lions”. Photo: Cubs of the Simba East pride: too young to kill but old enough to crave meat. Adult females, and sometimes males, do the hunting. Zebras and wildebeests rank high as chosen prey in the rainy season. (Photo by Michael Nichols/National Geographic via The Atlantic)