A Houthi follower with fake blood on his clothes lies on the ground to represent a victim as others perform a war dance during a ceremony marking the first anniversary of the Houthi movement's takeover of Yemen's capital Sanaa September 21, 2015. (Photo by Khaled Abdullah/Reuters)

A man rides his loaded tricycle next to three schoolgirls in Shanghai on December 11, 2015. (Photo by Johannes Eisele/AFP Photo)

A woman photographs “Super Space Titan Kitty” by Colin Christian at the “Hello! Exploring the Supercute World of Hello Kitty” museum exhibit in honor of Hello Kitty's 40th anniversary, at the Japanese American National Museum in Los Angeles, California October 10, 2014. (Photo by Lucy Nicholson/Reuters)

Arizona Cardinals cheerleader Claire Thorton, center, smiles as Air Force Capt. Eric Straub proposes to her during the first half of an NFL football game against the Washington Redskins, Sunday, October 12, 2014, in Glendale, Ariz. Thorton accepted the proposal. (Photo by Rick Scuteri/AP Photo)

A woman is tattooed by an artist during Warsaw Tattoo Convention 2014 in Warsaw November 29, 2014. (Photo by Kacper Pempel/Reuters)

Soldiers of People's Liberation Army (PLA) Lanzhou Military Region jump through a burning obstacle during a training session at a military base in Tianshui, Gansu province, China, January 6, 2016. (Photo by Reuters/Stringer)

A news crew runs from flames southeast of Middletown, Calif., on Tuesday, September 15, 2015, as winds kick up the Valley fire. (Photo by Wally Skalij/Los Angeles Times/TNS)

Cycling jerseys, part of a collection belonging to French cycling fan Gerald, hang from a line during the 4th stage of the Tour de France cycling race from Seraing in Belgium to Cambrai in France, July 7, 2015. Photographing the Tour de France cycling race comes with highs and lows: the buzz from capturing just the right image, the tedium of long journeys, the painstaking set-up of equipment, the breath-taking scenery. Reuters photographers have worked not only to capture the thrills and spills on the roads and mountain passes. They have also shot a set of pictures showing their own quirky view from behind the scenes as they travelled through the Netherlands, Belgium and France. (Photo by Eric Gaillard/Reuters)