An exercise rider takes a horse for a morning workout at Saratoga Race Course on Thursday, July 23, 2015, in Saratoga Springs, N.Y. (Photo by Mike Groll/AP Photo)

A Pakistani family enjoy a camel ride at the Karachi beach, in Pakistan, Tuesday, August 4, 2015 in Pakistan. (Photo by Fareed Khan/AP Photo)

A boat floats through light reflected from the illuminated Ada Bridge over the Sava river in Belgrade, Serbia, late Monday, July 20, 2015. (Photo by Darko Vojinovic/AP Photo)

Sun and a cloudy sky as Indian vendors steer a bamboo rack at the bank of the Brahmaputra river in Guwahati city, India, July 25, 2015. The 2,900 km long Brahmaputra River is trans-boundary river and one of Asia's longest rivers. It passes through Tibet into India and Bangladesh before flowing into the Bay of Bengal. (Photo by EPA/Stringer)

An egret flies above the banks of Poyang, the country’s largest freshwater lake in Jiujiang, China on August 3, 2015. (Photo by Fu Jianbin/Xinhua Press/Corbis)

A woman holding her mobile phone walks past a display window outside a cosmetic company at Tokyo's Ginza shopping district in Japan, July 20, 2015. (Photo by Yuya Shino/Reuters)

People walk on the embankment at the river Spree during sunset in Berlin, Germany, July 21, 2015. (Photo by Fabrizio Bensch/Reuters)

A roller skater performs a trick at a skate park in Ciudad Juarez, Mexico, July 21, 2015. (Photo by Jose Luis Gonzalez/Reuters)

A boy is silhouetted as he paddles on a stand up board during sunset on Lake Zicksee in St. Andrae, Austria, July 24, 2015. (Photo by Leonhard Foeger/Reuters)

Athletics, IAAF Diamond League 2015, Sainsbury's Anniversary Games, Queen Elizabeth Olympic Park, London, England, on July 25, 2015: Poland's Piotr Lisek in action during the men's pole vault final. (Photo by Phil Noble/Reuters)

A man throws a girl into the air during sunset as they spend time on the territory of Chersonesus Tavrichesky (Tauric Chersonesos) National Reserve in the Black Sea port of Sevastopol, Crimea, July 25, 2015. (Photo by Pavel Rebrov/Reuters)

A hiker takes a picture of the sunrise while touring La Huasteca park, on the outskirts of Monterrey, Mexico, July 26, 2015. (Photo by Daniel Becerril/Reuters)

A visitor is silhouetted as she slides down a huge water pipe at a public swimming pool on a hot sunny day in Vienna, Austria, July 22, 2015. (Photo by Leonhard Foeger/Reuters)

Visitors at the Musee d'Orsay are seen in silhouette as they look behind a giant clock face at the former Orsay railway station, in Paris, France July 28, 2015. The national museum of the Musee d'Orsay opened in December 1986 and it displays collections of art from the period 1848 to 1914. France has been the world's most visited country since the 1980's, welcoming 84 million tourists last year. (Photo by Stephane Mahe/Reuters)

A seagull stands on a sculpture by Spanish artist Jaume Plensa at sunset on the place Massena in Nice, July 30, 2015. (Photo by Eric Gaillard/Reuters)

A full moon, known as the Blue Moon, rises behind a telecommunication tower over the Camlica Hill in Istanbul, Turkey, July 31, 2015. (Photo by Murad Sezer/Reuters)

A brilliant sunset makes for a fun silhouette picture by jumping between sand bars at Shi Shi Beach on the Olympic Peninsula Friday July 17, 2015. (Photo by Bettina Hansen/The Seattle Times)

Two cranes with the French construction group Bouygues company logo are seen in the morning sky in Orly, France, near Paris, August 1, 2015. (Photo by Stephane Mahe/Reuters)

A woman is seen silhouetted while walking a dog at sunset on Manhasset Bay in Port Washington, New York August 5, 2015. (Photo by Shannon Stapleton/Reuters)

A photo made available 21 July 2015 of the glowing band of the so-called “Milky Way” seen in the summer night sky over the vicinity of Salgotarjan, 109 kilometers northeast of Budapest, Hungary, late 20 July 2015. The “Milky Way” is the galaxy that contains our own Solar system and appears as a disc shape bright band in the sky, although it can rarely been seen by the naked eye. (Photo by Peter Komka/EPA)

Two children are silhouetted as they observe a person on a stand up board during sunset on Lake Zicksee in St. Andrae, Austria, July 24, 2015. (Photo by Leonhard Foeger/Reuters)

Tourists watch the sunrise above a sea of fog on Eggishorn moutain (2927 meters over sea level), in Fiesch, Switzerland, early Tuesday, July 28, 2015. (Photo by Dominic Steinmann/Keystone via AP Photo)

Ocean paddlers train on surf ski's at Manly Beach on July 28, 2015 in Sydney, Australia. (Photo by Cameron Spencer/Getty Images)

A girl walks through a shadow under the Ada bridge in Belgrade, Serbia, Tuesday, July 21, 2015. (Photo by Darko Vojinovic/AP Photo)

Clouds of an approaching thunderstorm are seen from the puszta or Hungarian steppe of Hortobagy, 183 kms east of Budapest, Hungary, Tuesday, August 4, 2015. (Photo by Zsolt Czegledi/MTI via AP Photo)

People riding an attraction are silhouetted as the sun sets beyond Worlds of Fun amusement park, Thursday, July 30, 2015, in Kansas City, Mo. (Photo by Charlie Riedel/AP Photo)

In this photo taken December 22, 2014, from left, Bert Bouma, Mark Viergutz and Kal Poole examine the backdrops at the Consistory Shrine Temple in Helena, Mont. (Photo by Thom Bridge/The Independent Record via AP Photo)

A plane is silhouetted as the sun sets beyond Worlds of Fun amusement park, Thursday, July 30, 2015, in Kansas City, Mo. (Photo by Charlie Riedel/AP Photo)

A firefighting air tanker flies in front of the setting sun while battling the Rocky Fire on August 1, 2015 near Clearlake, California. (Photo by Justin Sullivan/Getty Images)

An Afghan farmer carries a bundle of wheat during harvest, at sunset on the outskirts of Mazar-i-Sharif, August 3, 2015. (Photo by Farshad Usyan/AFP Photo)

A paddleboarder and dog travel along Shuswap Lake as the sun sets in Sicamous, British Columbia. (Photo by Jason Franson/The Canadian Press via AP Photo)