In this Wednesday, December 2, 2015 photo, Dr. Gal Kelmer, head of the department of large animals, unties a horse after its operation at the University's Koret School of Veterinary Medicine in Rishon Lezion, Israel. “Horses have an instinctive response of flight from danger”, Kelmer said. “The minute they wake up they start trying to stand and run, even if they don't have control of their limbs. So then they fall”. (Photo by Oded Balilty/AP Photo)

In this October 15, 2014 file photo, Katsu Nakamura, sky division manager for Yamaha USA, moves the RMax unmanned helicopter into position before a demonstration of its aerial application capabilities at the University of California, Davis' Oakville Station test vineyard in Oakville, Calif. Researchers at UC Davis have been studying the effectiveness of the drone's ability for spraying pest control and nutritional materials on the test vineyard in California's Napa Valley. (Photo by Rich Pedroncelli/AP Photo)

A undated handout image provided by the Bochum University of Applied Sciences (Hochschule Bochum) on 04 October 2013 shows the German team Bochum's Cruiser class solar car during a test drive in the Northern Territoty, Australia, 16 September 2013. The Dutch vehicle is competing in the World Solar Challenge, driving from Darwin to Adelaide starting on 06 October 2013. (Photo by Hochschule Bochum/EPA)

Lisandra Perez, 7, practices in his house before his flute lesson at the Integral System of Artistic Education for Social Inclusion (SIFAIS) center in the poor neighborhood of La Carpio, Costa Rica October 8, 2015. SIFAIS center is developing a social program with the help of 156 volunteers who teach art, music, sports and education, for children and youth living in La Carpio, known for being the home to gangs, violence, drugs and social vulnerability, according to the centre. (Photo by Juan Carlos Ulate/Reuters)

An aspiring Catholic priest Jose Luis Guerra, a member of Raza Nueva in Christ, a project of the archdiocese of Monterrey, and other missionaries hand out a Bible to Angel Castillo, who wants to become a missionary with Raza Nueva, in the municipality of Garcia, outskirts of Monterrey, Mexico, July 12, 2016. In the troubled fringes of the northern Mexican city of Monterrey, an aspiring priest is using his faith to reach out to young gang members and at-risk youth, and bring them into his “Gang of Christ”. (Photo by Daniel Becerril/Reuters)

Belarussians in costumes sing songs during the traditional rite of Shchadrets (Schedry vecher or Generous Eve) in the village of Osovo, some 190 km from Minsk, Belarus, 13 January 2015. Shchadrets is a Belarusian folk holiday celebrated on the New Year's Eve in accordance with the Julian calendar (Old New Year). The holiday is similar to Koliady, when youth in costumes walk from house to house singing holiday songs, performing, and asking for a reward afterwards. (Photo by Tatyana Zenkovich/EPA)

Women sing and dance as children gather in the background during the so-called parade of children's troops in Rostov-on-Don, southern Russia, May 14, 2015. About 500 children aged from 4 to 10, members of youth military patriotic clubs, honor guards and paratroopers took part in the event, which was organized under the guidance of Commander of Southern Military District Colonel-General Alexander Galkin and was held to honor World War Two veterans and mark the 70th anniversary of the victory over Nazi Germany, according to local media. (Photo by Eduard Korniyenko/Reuters)