Participants run through coloured powder during the YARKOcross colour run race in Almaty, Kazakhstan, June 5, 2016. (Photo by Shamil Zhumatov/Reuters)

Afghan protesters beat a policeman after a suicide attack that targeted crowds of minority Shiite Hazaras during a demonstration at the Deh Mazang Circle of Kabul on July 23, 2016. Islamic State jihadists claimed responsibility for twin explosions July 23 that ripped through crowds of Shiite Hazaras in Kabul, killing at least 61 people and wounding 207 others in apparently their deadliest attack in the Afghan capital. The bombings during a huge protest over a power transmission line could deepen sectarian divisions in a country well known for communal harmony despite decades of war. (Photo by Wakil Kohsar/AFP Photo)

Tube passengers take a selfie next to a London underground roundel designed for the launching of the Night Tubes on display at Oxford Circus underground station in London, Britain, 19 August 2016. The long delayed Night Tubes service launched on 19 August. The 24-hour service will operate on Fridays and Saturdays. (Photo by Hannah Mckay/EPA)

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)

A racegoers cheers on her horse in Race 4 ahead of the race of the Melbourne Cup at Flemington Racecourse in Melbourne, Australia, Tuesday, November 7, 2017. (Photo by Andy Brownbill/AP Photo)

In this January 29, 2017 photo, musicians perform for dancers on the shores of Lake Titicaca, as they practice before their presentation for the Virgin of Candelaria celebrations in Puno, Peru. Dancers in colorful masks and elaborate costume celebrate the Virgin of Candelaria, patron saint of communities along the shore of Lake Titicaca, in what's considered the largest Catholic festival in the Andes. (Photo by Rodrigo Abd/AP Photo)

A recruitment drive during the First World War at Trafalgar Square, London. (Photo by Central Press/Getty Images)

Brad Snead walks past melting ice on the Cook Inlet beach, Saturday, March 26, 2011, in Kenai, Alaska, while looking for agates. (AP Photo/Peninsula Clarion, M. Scott Moon)