Mary Ellen Mark was an American photographer known for her photojournalism / documentary photography, portraiture, and advertising photography. She photographed people who were "away from mainstream society and toward its more interesting, often troubled fringes". Here: Amanda and her cousin Amy, Valdese, North Carolina, 1990. (Photo by Mary Ellen Mark)

Palestinian girls take part in a ballet dancing course, run by the Al-Qattan Center for Children, in Gaza City November 25, 2015. (Photo by Suhaib Salem/Reuters)

Jack London was a prolific photographer in addition to his writing. Here: Salvation Army barracks in London during Sunday morning rush – men who had been given tickets during the night queuing for free breakfast, 1902. (Photo by Jack London/Courtesy of Contrasto)

Revellers from Russia parade during the Aoussou Carnival in Sousse, Tunisia July 26, 2015. (Photo by Anis Mili/Reuters)

This extraordinary series of close-up photos turns mundane insects into terrifying beasts from another world. The bugs are captured in intricate detail by photographer Javier Ruperez, using a special lens, revealing just how complex the tiny creatures are. (Photo by Javier Ruperez/Solent News & Photo Agency)

Blow-up unicorns, a pig on a pulley and chickens on the lam populate the polychrome pictures in this year’s LensCulture street photography awards. Here: Subida Al Cielo, by José Nieto. Finalist, single image. (Photo by José Nieto/LensCulture 2018 Street Photography Awards)

Graham Fink has been documenting the demolition sites of Shanghai for five years, trying to capture the state of flux during this period of rapid urbanisation. His Ballads of Shanghai exhibition is at London’s Riflemaker gallery until Sunday. Here: “Big Dreams”. (Photo by Graham Fink/Riflemaker)

A Hypsiboas crepitans frog is pictured at a terrarium in Caracas November 30, 2015. Venezuelan frogs and toads are in critical danger due to climate change as rising temperatures complicate reproduction and spread a deadly fungus, say scientists, who liken the species to canaries in a coalmine warning of imminent danger. The survival of a group of nearly 20 frog and toad species, which top Venezuela's list of endangered species, may rest on a small group of academics in a Caracas laboratory attempting to recreate the amphibians' natural reproductive conditions. (Photo by Carlos Garcia Rawlins/Reuters)