Dan McManus and his service dog Shadow hang glide together outside Salt Lake City, Utah, July 22, 2013. McManus suffers from anxiety and Shadow's presence and companionship help him to manage the symptoms. The two have been flying together for about nine years with a specially made harness for Shadow. (Photo by Jim Urquhart/Reuters)

An activist kicks the shields of the military police officers during a demonstration in the military zone of the 27th infantry battalion in Iguala, Guerrero, January 12, 2015. Activists and relatives of the 43 missing trainee teachers from Ayotzinapa's teacher training college broke into the military zone, located less than a mile from where the students went missing, in an attempt to look for the missing students.The remains of only one of the 43 students has been identified so far. (Photo by Jorge Dan Lopez/Reuters)

An installation consisting of a series of bird boxes is displayed in a tree in Duncan Terrace Gardens in Islington on March 24, 2011 in London, England. The boxes by artists Bruce Gilchrist and Jo Joelson of “London Fieldworks”, were designed to reflect the architecture of the Georgian terraces and flats that surround the park in the community gardens. (Photo by Dan Kitwood/Getty Images)

A Sotheby's employee holds a 110.03 carat sun-drop diamond on October 24, 2011 in London, England. The diamond is the largest yellow pear-shaped diamond in the world, and is expected to fetch between $11-15 Million USD when it is sold at auction at Sotheby's Auction house in London. (Photo by Dan Kitwood/Getty Images)

The under-construction Shard building on December 5, 2011 in London, England. The 80 storey skyscraper will be Europe's tallest mixed-use building when it is completed in May 2012; it will contain offices, restaurants, residential apartments as well as a five star hotel. (Photo by Dan Kitwood/Getty Images)

Girls look at a newly installed “Renew” media point in the City of London on January 26, 2012 in London, England. The “pods” will transmit each market day and will include breaking news, weather and travel information, and information about sport, fashion, the arts and entertainment. The stations which will also double as recycling points are run by media company Renew. (Photo by Dan Kitwood/Getty Images)

Ary Borges feeds his tiger named Dan at his home in Maringa, Brazil, Thursday, September 26, 2013. Borges is in a legal battle with federal wildlife officials to keep his endangered animals from undergoing vasectomies and being taken away from him. He defends his right to breed the animals and says he gives them a better home than they might find elsewhere in Brazil. (Photo by Renata Brito/AP Photo)

People appear dangling as a large-scale installation art piece by Leandro Erlich, named “Dalston House”, in London, England. Part of the “Beyond Barbican” summer series of events, the interactive installation is a full facade of a late nineteenth-century Victorian terraced house built on the ground with a large mirror above it to reflect people as to appear dangling from the structure. (Photo by Dan Dennison)