Libyan forces allied with the U.N.-backed government fire a shell at Islamic State fighters' positions in Sirte, Libya August 15, 2016. (Photo by Ismail Zitouny/Reuters)

A model falls and gets help back to her feet during the fashion show for the Givenchy Spring 2016 collection at Fashion Week on, Friday, September 11, 2015, in New York. (Photo by Bebeto Matthews/AP Photo)

Boys ride a motorbike on their way back home after taking a bath in a canal at Chachura village, in Uttar Pradesh April 4, 2012. (Photo by Parivartan Sharma/Reuters)

Runners gather at the start line for the annual “Santa Speedo Run”, a charity race through the streets of the Back Bay neighborhood of Boston. (Photo by Gretchen Ertl/Reuters)

Children play at the Ryoji Ikeda exhibition “the transfinite” at the Park Avenue Armory on June 10, 2011 in New York City. The audio visual installation, which will close after tomorrow, features two back-two-back screens displaying a continual loop of sounds, fragments of numbers and strobe-lit patterns that echo the Japanese artist's interest in mathematics, the subconscious and the digital world. (Photo by Spencer Platt/Getty Images)

An Indian villager walks back home with a bicycle loaded with grass for his cattle during a heavy downpour on the outskirts of Bhubaneswar, India, Saturday, 11 July 2015. (Photo by Biswaranjan Rout/AP Photo)

Participants run through the streets of the Back Bay during the 16th annual Santa Speedo Run in Boston, Massachusetts, December 12, 2015. (Photo by Brian Snyder/Reuters)

Labourers load a three-wheeled vehicle onto the back of a van at the Mercato market in Addis Ababa October 9, 2015. Addis Ababa's “Mercato” – Italian for “market” – is reputedly the biggest open-air market in Africa, lying in the west of the capital. (Photo by Tiksa Negeri/Reuters)