Colombian police help carry people's household belongings across the Tachira River from Venezuela, top, to Colombia, on the border that separates San Antonio del Tachira, Venezuela from Villa del Rosario, Colombia, Tuesday, August 25, 2015, during a mass exodus of Colombians. Venezuelan President Nicolas Maduro vowed to extend a crackdown on illegal migrants from neighboring Colombia he blames for rampant crime and widespread shortages, while authorities across the border struggled to attend to droves of returning deportees. (Photo by Eliecer Mantilla/AP Photo)

A woman waits at a polio immunisation health centre, in Maiduguri, Borno State, Nigeria, August 29, 2016. Nigeria's military has liberated large swathes of land from Boko Haram but a ride with an army convoy, all guns firing for fear of ambush, shows how far the northeast is from normality after a brutal Islamist insurgency that has displaced millions. (Photo by Afolabi Sotunde/Reuters)

Many of the 12 million people who entered the US through New York’s Ellis Island wore traditional dress from their homelands. Here: A Ruthenian woman circa 1906 from the region historically inhabiting the kingdom of the Rus, incorporating parts of modern-day Slavic speaking countries. Her outfit consists of a shirt and underskirt made from linen embroidered with traditional floral-based patterns. (Photo by Augustus Francis Sherman/New York Public Library/The Guardian)

Nine years ago, Tom Carter traveled from San Francisco to China, responding to a job posting that turned out to be a scam. He managed to find another job as a teacher, and saved enough money to embark on a 56,000 km trip through all of China's 33 provinces that lasted two years. Carrying a camera – just a a 4-megapixel point-and-shoot – Carter captured some amazing images of the widely varying landscape, people, and architecture across the nation. Photo: Buddhist pilgrim family from Sichuan. (Photo by Tom Carter via The Atlantic)

A recently rescued grey seal pup looks up from its indoor kennel at the RSPCA West Hatch Wildlife Centre on January 9, 2012 in Taunton, England. The centre is currently dealing with a number of mainly grey seals that have been rescued from the coast due to the recent storms. Staff at the centre hope to release all the seals back into the wild by the spring. (Photo by Matt Cardy/Getty Images)

Charlotte Roirdan from Lyon & Turnbull views a letter written by Mary Queen of Scots on March 8, 2012 in Edinburgh, Scotland. The 450 year old letter, unearthed in Blair Castle in Ayrshire, has been verified as the hand writing of Mary Queen of Scotts and has been valued at 3,000 GBP. The letter, dated March 20, 1554, relieves the then laird of Blair from his duties due to gout and will be put up for sale next week at an auction in Edinburgh. (Photo by Jeff J. Mitchell/Getty Images)

Elena Chernyshova's vision of Norilsk, Russia, the northernmost city in the world, is a series of surprises by which she extracts otherworldly beauty from ugly realities. Here: 2013. A woman is visible through a narrow passageway between two buildings. Norilsk's urban spaces were designed to shorten distances around large developments and give residents maximum protection from arctic winds. (Photo by Elena Chernyshova)

An arrow-head discovered in 2006 by Archaeologists of the University of Cambridge Archaeological Unit, is displayed by one of the team uncovering Bronze Age wooden houses, preserved in silt, from a quarry near Peterborough, Britain, January 12, 2016. Archaeologists said on Tuesday they had discovered what were believed to be the best-preserved Bronze Age dwellings ever found in Britain, providing an extraordinary insight into prehistoric life from 3,000 years ago. (Photo by Peter Nicholls/Reuters)