Natasha Hastings of U.S. on the starting block before the women's 400 metres heats during the 15th IAAF World Championships at the National Stadium in Beijing, China August 24, 2015. (Photo by Lucy Nicholson/Reuters)

Milena Pino, 15, puts on makeup prior to taking part in a speed competition with horses at the International Livestock Fair Show in Havana March 21, 2015. (Photo by Alexandre Meneghini/Reuters)

A pair of young visitors rushes through a tunnel of colored lights at the annual Garden of Lights display at Brookside Gardens on December, 06, 2015 in Silver Spring, MD. (Photo by Bill O'Leary/The Washington Post)

A man walks though Times Square in high heels during unseasonably warm weather on Christmas Eve in the Manhattan borough of New York December 24, 2015. (Photo by Carlo Allegri/Reuters)

Laura Paipo (L), first blind principal in Uruguay participates in a street race with her sighted guide and friend Amparo Bauter in Montevideo, October 4, 2015. Paipo, 55, who took office on August 10, 2015 became the first blind principal of a special school which specializes in the education of visually impaired students. (Photo by Andres Stapff/Reuters)

A supercell that spawned a tornado earlier makes it was east north of McLean, Texas on April 16, 2015 in Texas, United States. Huge hail, terrifying lighting and giant supercells the size of buildings – these incredible images depict a year in the life of a storm chaser. Shot in 2015 by photographer Mike Olbinski, 40, this series of pictures show both the beautiful and the extreme nature of weather in the United States. (Photo by Mike Olbinski/Barcroft Media)

Ten-year-old Macy Friday, front left, reacts as she looks back at her family after meeting Hillary Clinton, front right, as she campaigns for U.S. Sen. Mark Udall, D-Colo., back, during a stop in the newly-renovated Union Station in Denver on Monday, October 13, 2014. Clinton appeared at an event to raise money for Udall's current re-election campaign and then headed to Las Vegas for another appearance on Monday night. (Photo by David Zalubowski/AP Photo)

Alexo Carmona, 2, looks at Coco, a two-year-old pony, in downtown Havana, in this March 6, 2015 file photo. Nearly a quarter of a million people follow the Reuters Instagram account – and it's still growing fast. To mark the mid-point of 2015, Reuters has compiled the twenty most-liked pictures so far. This picture was 20th most popular. (Photo by Alexandre Meneghini/Reuters)