A woman loyal to the Houthi movement holds a rifle as she takes part in a parade to show support to the movement in Sanaa, Yemen September 6, 2016. The Saudi-led Arab coalition launched a military campaign against the Huthis and their allies in March 2015, after the rebels closed in on Gulf-backed President Abedrabbo Mansour Hadi in his southern refuge of Aden, forcing him into exile. (Photo by Khaled Abdullah/Reuters)

The Red Arrows make a flypast during the Trooping The Colour parade at Buckingham Palace, in London, Saturday, June 13, 2015. Hundreds of soldiers in ceremonial dress have marched in London in the annual Trooping the Color parade to mark the official birthday of Queen Elizabeth II. The Trooping the Color tradition originates from preparations for battle, when flags were carried or "trooped" down the rank for soldiers to see. (AP Photo/Tim Ireland)

Indonesian child jockey Egi, 8, poses for photographs as he participates in a traditional horse race marking Indonesia's 70th independence anniversary, in Bima, West Nusa Tenggara province, Indonesia, 08 August 2015. Horse racing is the traditional sport in the area and a cultural heritage which continues to be preserved by the people of Bima, a small city on the east side of Sumbawa island. Similar races also held in Sumbawa Besar regency and Dompu regency. (Photo by Mast Irham/EPA)

Dustin Murley (L) and Jessey Sisson race on their ostriches during the annual Ostrich Festival in Chandler, Arizona March 10, 2013. (Photo by Joshua Lott/Reuters)

A sign marks a railway crossing next to the troubled Kruemmel nuclear power plant on June 2, 2011 in Geesthacht, Germany. The German government recently announced it will phase out the country's 17 remaining nuclear reactors by 2022 in a policy initiative that represents a radical reversal from its previous policy and was sparked by the disaster at Fukushima. Kruemmel went into operation in 1983 but was taken offline following a fire in 2007. (Photo by Sean Gallup/Getty Images)

Cyril Despres of France tries to get his Peugeot out of the sand as co-pilot David Castera pushes the car during the 10th stage of the Dakar Rally 2016 near Fiambala, Argentina, January 13, 2016. (Photo by Marcos Brindicci/Reuters)

In this May 1, 2016 photo, a reluctant donkey is alternately pushed and pulled and enticed with carrots toward town hall in order to be dressed for the costume competition at the annual donkey festival in Otumba, Mexico state, Mexico. Otumba was an important donkey market during Spanish colonial times, standing at the crossroads of major roads leading to Mexico City, where the beasts pulled heavy loads and carried travelers. Today, however, farmers use tractors and pickup trucks, and the donkey population is in decline. (Photo by Rebecca Blackwell/AP Photo)

A couple watches the sunset over a sea of fog covering the Geneva Lake from Chardonne, Switzerland, 28 December 2015. (Photo by Jean-Christophe Bott/EPA)