Marines finish a 10 kilometer training hike carrying 55 pound (25 kg) packs during Marine Combat Training (MCT) on February 22, 2013 at Camp Lejeune, North Carolina. Since 1988 all non-infantry enlisted male Marines have been required to complete 29 days of basic combat skills training at MCT after graduating from boot camp. MCT has been required for all enlisted female Marines since 1997. About six percent of enlisted Marines are female. (Photo by Scott Olson/AFP Photo)

Sebastião Salgado is a Brazilian documentary photographer living in Paris. He has produced several books, and his work has been exhibited extensively around the world. His latest work, «Genesis», premieres at The Natural History Museum in London on April 11, on view through September 8, 2013. Photo: On South Georgia, a barren island in the far South Atlantic, a pair of southern elephant seal calves beckon before a colony of king penguins. “The male seals can grow to almost five tons,” says Salgado, “but these are just babies. This one looked at me with beautiful eyes”. (Photo by Sebastião Salgado/Amazonas/Contact Press Images)

A lone male cheetah is set upon by a pack of African wild dogs. Peter Haygarth had been following the dogs as they hunted in Zimanga Private Game Reserve in KwaZulu-Natal, South Africa. On first encountering the cheetah, the dogs were wary, but as the rest of the pack arrived, their confidence grew and they began to encircle the cat. Peter kept his focus on the cat’s face. In a few minutes the spat was over as the cheetah fled. (Behaviour: mammals category). (Photo by Peter Haygarth)

Ultra-orthodox Jewish men wearing protective face masks swim in the Mediterranean Sea, on a beach segregated for males three days a week, in Tel Aviv, Israel, Wednesday, July 8, 2020. In an effort to quell the rapid spread of the coronavirus, Israel has re-imposed a series of restrictions on the public. This week, the Israeli government limited gatherings and ordered reception halls, restaurants, bars, theaters, fitness centers and pools be shut down again. (Photo by Oded Balilty/AP Photo)

A Bolivian Squirrel monkey plays with a toy football at London Zoo on August 18, 2011 in London, England. Male monkey Bounty has fathered eleven baby monkeys in the last three years since his arrival, enough to make up a football team. His latest offspring named Rolo was the eleventh and arrived last month. (Photo by Dan Kitwood/Getty Images)

Ten day old male Gorilla “Fataki” clings to his mother “Frala” during his media debut at Taronga Zoo June 4, 2003 in Sydney, Australia. Fataki was born on May 24, 2003 and was the fourth Gorilla to be born at Taronga Zoo since the opening of the Gorilla Forest in 1997. (Photo by Chris McGrath/Getty Images)

“The last known individual of the subspecies was a male named Lonesome George (Spanish: El Solitario Jorge/George), who died on 24 June 2012. In his last years, he was known as the rarest creature in the world. George served as a potent symbol for conservation efforts in the Galápagos and internationally”. – Wikipedia. (Photo by Rodrigo Buendia/AFP)

A baby Asian elephant, born only two days before, stands next to his mother Nova in its enclosure at Tierpark Berlin Zoo on May 10, 2012 in Berlin, Germany. The male elephant calf, who does not have a name yet, weighs 102kg and is 91cm tall. (Photo by Timur Emek/dapd/Sean Gallup)