American soldiers with the 173rd Airborne Brigade Battle Company, on a battalion-wide mission in the Korengal Valley, looking for caves, weapons caches and known Taliban leaders, 2007. Tanner Stichter tends to Spc. Carl Vandeberge in the bushes moments after Vandeberge was shot in the stomach during a Taliban ambush, which killed one soldier and wounded two others. (Photo by Lynsey Addario)

Corey Arnold is a fine art photographer and a commercial fisherman, working the stormy waters of the Bering Sea by Alaska. His latest work documents life in this remote wilderness, both at sea and on the shore, capturing trawlers, foxes, eagles and the grandeur of the scenery. “Aleutian Dreams” can be seen at Charles A Hartman Fine Art in Portland, Oregon, until 27 May. Here: “Roadside Friend”. (Photo by Corey Arnold/Charles A. Harman Fine Art/The Guardian)

At the beginning of the 20th century, Edward S. Curtis set out to document what he saw as a disappearing race: the Native American. From 1907 to 1930, Curtis took more than 2,000 photos of 80 tribes stretching from the Great Plains to the Pacific Northwest and Alaska. He then published and sold these photos, along with narrative text, in 20 volumes of work known as “The North American Indian”. It is one of the most significant collections of its kind, “probably the most important photographic document of its age and its topic,” said Jeffrey Garrett, associate university librarian for Special Libraries at Northwestern University. (Photo by Edward S. Curtis)

“A dirty thunderstorm (also, Volcanic lightning) is a weather phenomenon that occurs when lightning is produced in a volcanic plume. Dirty thunderstorms have been reported in Chile above the Chaiten Volcano, above Alaska's Mount Augustine volcano, and Iceland's Eyjafjallajökull volcano”.

Photo: A cloud of ash pours from Puyehue volcano in southern Chile, at sunset on June 5, 2011. (Claudio Santana/AFP)

“A Hawaiian photographer braved freezing temperatures for this cold SNAP – of what appears to be a firebird bursting from an aurora. Keen snapper CJ Kale, more used to sun, sea and sand while at work than snow, captured the incredible moment while on a trip to Alaska. It was his first time seeing the spectacular sight and lucked out – capturing some of the rarest colors of aurora on his first night”. – Caters News

“The Red River Hog (Potamochoerus porcus), also known as the Bush Pig (but not to be confused with P. larvatus, common name “Bushpig”), is a wild member of the pig family living in Africa, with most of its distribution in the Guinean and Congolian forests. It is rarely seen away from rainforests, and generally prefers areas near rivers or swamps.

Red River Hogs eat grass, berries, roots, insects, molluscs, small vertebrates and carrion. They are capable of causing damage to plantations. Red River Hogs typically live in herds of 6-20 members led by a dominant boar. Sows rear 3-6 piglets at a time.”

Photo: Two 17 day old red river hoglet twins forage for food next to their mother Bahiti at London Zoo on August 23, 2007 in London, England. Red River hoglets inhabit the forests and swamps of West and Central Africa. The recent additions to the London Zoo pig pen have been eagerly awaited by zoo keepers. (Photo by Chris Jackson/Getty Images)

“The nuclear football (also known as the atomic football, the president's emergency satchel, the button, the black box, or just the football) is a briefcase, the contents of which are to be used by the President of the United States of America to authorize a nuclear attack while away from fixed command centers, such as the White House Situation Room. It functions as a mobile hub in the strategic defense system of the United States. It is a metallic Zero Halliburton briefcase carried in a black leather “jacket”. The package weighs around 45 pounds (20 kilograms). A small antenna protrudes from the bag near the handle”. – Wikipedia

Photo: A U.S. Military officer carries the “football”, which carries nuclear launch codes, on South Lawn after returning with U.S. President George W. Bush to the White House January 7, 2002 in Washington, DC. (Photo by Mark Wilson/Getty Images)

In this photo taken Friday, September 4, 2015, tourists Sarah and John Scott from Worcester, England, take a step back as a male silverback mountain gorilla from the family of mountain gorillas named Amahoro, which means “peace” in the Rwandan language, unexpectedly steps out from the bush to cross their path in the dense forest on the slopes of Mount Bisoke volcano in Volcanoes National Park, northern Rwanda. Deep in Rwanda's steep-sloped forest, increasing numbers of tourists are heading to see the mountain gorillas, a subspecies whose total population is an estimated 900 and who also live in neighboring Uganda and Congo, fueling an industry seen as key to the welfare of the critically endangered species as well as Rwanda's economy. (Photo by Ben Curtis/AP Photo)