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)

A Syrian Democratic Forces (SDF) female fighter adjusts a mortar in northern Deir al-Zor province ahead of an offensive against Islamic State militants, Syria February 21, 2017. (Photo by Rodi Said/Reuters)

The Pink Floyd inflatable pig floats next to Broadcasting House to promote their new exhibition at the V&A museum, in London, Britain May 10, 2017. (Photo by Neil Hall/Reuters)

Activists in a clay outfits at the Rathausmarkt during the art protest campaign “1000 Gestalten” (lit 1000 figures), for more solidarity and political participation, in Hamburg, Germany, 17 June 2017. In a two-hour show hundreds of actors took part in a creative public appeal for more humanity and self-responsibility ahead of the upcoming G20 summit. The G20 economic summit takes place in Hamburg July 7-8. (Photo by Lukas Barth-Tuttas/DPA/Alamy Live News)

In this February 4, 2016 picture a masked participant of the traditional carnival parade poses in the streets of the village of Kippel in the Loetschental valley, southwestern part of Switzerland. During this sinister carnival, participants wearing wooden masks and animal furs, crowd the streets of the villages to scare the people. (Photo by Dominic Steinmann/Keystone via AP Photo)

Fashion models Darien Leigh and Valerie Drew play leap-frog on the beach. 2nd July 1956. (Photo by Harry Kerr). P.S. All pictures are presented in high resolution.

Scores of internally displaced Muslims are at the heart of the humanitarian crisis in Central African Republic, where violence between Christians and Muslims has threatened to spiral into genocide. Photo: An internally displaced woman carries her child in a camp for internally displaced people (IDPs), located at Bangui International Airport, April 10, 2014. (Photo by Goran Tomasevic/Reuters)

A caterpillar driven ferry with a 24 horsepower engine takes holidaymakers from the mainland at Bigbury in Devon to Burgh Island, a quarter of a mile away. (Photo by Reg Speller/Fox Photos/Getty Images). 4th April 1935