Prospective flight attendants listen to their instructor during an etiquette training course at Indigo Airlines' Ifly training centre in Gurgaon on the outskirts of New Delhi November 18, 2014. (Photo by Adnan Abidi/Reuters)

Street photographer Yassine Alaoui Ismaili follows 16-year-old Emeer Guesmi, aka B-boy Zulu Rema, as he trains and performs breakdance moves – all without the use of his legs. At a breakdance championship in Tunisia, Casablanca-based street photographer Yassine Alaoui Ismaili noticed an unusual competitor: Emeer Guesmi, dancing without the aid of his lower legs. He started following him as he trained and performed. (Photo by Yassine Alaoui Ismaili/The Guardian)

Residents (R to L) Luiza, Janubie, Leiticia and Lucas sit beneath an overpass near their houses in an impoverished area in the unpacified Complexo da Mare slum complex, one of the largest “favela” complexes in Rio, on March 18, 2014 in Rio de Janeiro, Brazil. (Photo by Mario Tama/Getty Images)

A British woman plays a piano designed especially for people who are confined to bed. Date: 1935. (Photo by Mary Evans Picture Library/Caters News)

An Indian man stands dressed like Hindu god Shiva to attract alms from devotees during the Ambubasi festival at the Kamakhya Hindu temple in Gauhati, India, Sunday, June 22, 2014. The annual festival where hundreds of holy men from an esoteric form of Hinduism, gather to perform rituals at the temple begins on June 22. (Photo by Anupam Nath/AP Photo)

An actress dressed as Black Cat poses for a photo at the London Super Comic Convention at the ExCeL Centre on February 23, 2013 in London, England. Enthusiasts at the Comic Convention are encouraged to wear a costume of their favourite comic character and flock to the ExCeL to gather all the latest news in the world of comics, manga, anime, film, cosplay, games and cult fiction. (Photo by Jordan Mansfield)

A young Free Syrian Army fighter holds a rifle in Haresta neighbourhood of Damascus January 16, 2013. (Photo by Goran Tomasevic/Reuters)

A new monorail service in Houston, Texas, ready for its inaugural service. (Photo by Evans/Three Lions/Getty Images). Circa 1950