Sandrine Kerfante has had a fascination with “doubles” ever since meeting her mother’s twin as a child. In 2012, this lifelong captivation inspired her to create a blog called twin-niwt, which celebrates photographs of doubles in all their forms. “I’m fascinated by the idea of the duo, repetition, symmetry, reflection, mirror games and all the symbolism associated with it”, she says. “I think it’s a topic often present in photography, more or less consciously”. (Photo by Sandrine Kerfante/The Guardian)

In this photograph taken on June 28, 2015, a hiker in Hong Kong takes a picture of the city from a walking trail. The southern Chinese territory is crisscrossed by more than 180 miles of designated hiking trails. (Photo by Alex Ogle/AFP Photo)

Berlin-based artist Sebastian Bieniek unfolds the story of a two-faced female in his series of photographs “doublefaced”. Using an eye pencil and lipstick, bieniek simply draws an image of a face onto the side of skin. The sketch includes only one eye: carefully placed hair hides the rest of the face from view, revealing one, moving eye of the model. Blue, brown, awake, and sleeping variations create portraits with unique expressions and an illustrative sensibility. The 22 photographs of the hybrid girl expose her daily routine – drinking coffee, traveling on the train, taking a shower, and smoking cigarettes – capturing the daily life of a female with two faces.

A woman poses for photographs with traditional side dish Kimchi during the Seoul Kimchi Festival in central Seoul, South Korea, November 4, 2016. Kimchi made with cabbage, other vegetables and chili sauce and kimchi is the most popular traditional food in Korea. (Photo by Kim Hong-Ji/Reuters)

In 1994, after the fall of the Soviet Union, all Ukrainians had to get a new passport – and photographer Alexander Chekmenev was on hand to take their photos. The snatched extra shots he took are remarkable in their honesty and tenderness. (Photo by Alexander Chekmenev/The Guardian)

Asia Sawicka as Anastasia IV poses for a photograph prior to a rehearsal of the Circus of Horrors' latest show Voodoo, ahead of Halloween, at the Wookey Hole Caves Theatre near Wells on October 19, 2017 in Somerset, England. (Photo by Matt Cardy/Getty Images)

Hisakata Hiroyuki, a talented photographer from Japan, has managed to snap a group of mortal tomcats in a variety of high-flying kung fu poses. Using his own rapid-fire reactions, he photographs the lovable cats flying through the air, their legs and paws outstretched, like something out of an action movie. (Photo by Hisakata Hiroyuki/Caters News Agency)

Actress Sophia Loren teases the hair of critic Gene Shalit in New York, Tuesday, February 20, 1979. During the filming of a segment for the NBC television “Today” show. In the background is a large photograph of Miss Loren. The segment is scheduled for airing later this week. (Photo by Dave Pickoff/AP Photo)