Bosnian men urge their horses to pull logs up a hill during a competition in the Bosnian town of Sokolac 50 kms west of Sarajevo, Bosnia,on Monday, April, 13, 2015. The annual festival celebrates the centuries old tradition of pulling logs honoring the owners of the strongest horses. Owners of the horses gather from all over Bosnia and beyond, and compete in a show of horse strength. (Photo by Amel Emric/AP Photo)

Handler Jorge Garcia-Bengochea holds Honor, a miniature therapy horse from Gentle Carousel Miniature Therapy Horses, as they visit with patients at the Kravis Children's Hospital at Mount Sinai in the Manhattan borough of New York City, March 16, 2016. Some of the most powerful medicine delivered to young patients at Mount Sinai Hospital in New York on Wednesday came in a package less than 32 inches tall and with a tail. Honor, a 10-month-old colt with Gentle Carousel Miniature Therapy Horses, trotted into the hearts of dozens of children and teens being treated at the Manhattan hospital. (Photo by Mike Segar/Reuters)

Wojtek Kwiatkowski probably the most famous horse photographer. He is an author and a publisher of books about Arabians breeding all over the world.

Travellers ride their horse through the river during the Appleby Horse Fair on June 5, 2014 in Appleby, England. The Appleby Horse Fair has existed under the protection of a charter granted by James II since 1685 and is one of the key gathering points for the Romany, gypsy and traveling community. The fair is attended by about 5,000 travellers who come to buy and sell horses. The animals are washed and groomed before being ridden at high speed along the “mad mile” for the viewing of potential buyers. (Photo by Nigel Roddis/Getty Images)

An Andalusian horsewoman waits for the animal to drink water before a classical dressage contest during the Sacab Andalusian Horse Show in Coin, southern Spain, April 12, 2015. (Photo by Jon Nazca/Reuters)

A Nepalese army solder stand next to a horse during the “Ghodejatra” Horse Race festival, which is organised by the Nepal Army, in Kathmandu, Nepal, April 7, 2016. Ghode Jatra, the horse racing festival of Nepal, celebrated on the New Moon day of mid March or early April is among the important celebrations of the Kathmandu Valley. Grand horse parade including various acrobatic style of shows are performed by Nepal military at Tundikhel-a fenced parade ground located in the heart of Kathmandu city. (Photo by Navesh Chitrakar/Reuters)

Daniel Filip, Tech Lead Manager for Google Maps, carries the Trekker, a 15-camera device, while mapping the Inca citadel of Machu Picchu for Google Street View in Cuzco, Peru, August 11, 2015. (Photo by Pilar Olivares/Reuters)

A view of the construction site of the Chateau de Guedelon near Treigny in the Burgundy region of France, September 13, 2016. Blacksmiths, stonemasons and quarry men are hard at work in a Burgundy forest building a 13th-century-style castle using the most basic tools and materials, replicating the methods used hundreds of years ago to better understand them. (Photo by Jacky Naegelen/Reuters)