In this Wednesday, July 23, 2014 file photo, Omaha photographer Lane Hickenbottom photographs the night sky in a pasture near Callaway, Neb. With no moon in the sky, the Milky Way was visible to the naked eye. More than one-third of the world’s population can no longer see the Milky Way because of man-made lights, according to a scientific paper by Light Pollution Science and Technology Institute's Fabio Falchi and his team members, published on Friday, June 10, 2016. (Photo by Travis Heying/The Wichita Eagle via AP Photo)

A female Kurdistan Workers Party (PKK) fighter stands near a security position in Sinjar, March 13, 2015. Women fighters at a Kurdistan Workers Party (PKK) base on Mount Sinjar in northwest Iraq, just like their male counterparts, have to be ready for action at any time. Smoke from the front line, marking their battle against Islamic State, which launched an assault on northern Iraq last summer, is visible from the base. Many of the women have cut links with their families back home; the fighters come from all corners of the Kurdish region. (Photo by Asmaa Waguih /Reuters)

Migrants storm into a train at the Keleti train station in Budapest, Hungary, September 3, 2015 as Hungarian police withdrew from the gates after two days of blocking their entry. (Photo by Laszlo Balogh/Reuters)

A man runs after he tried to put himself on fire during a protest at a makeshift camp at the Greek-Macedonian border near the village of Idomeni on March 22, 2016. Greece will not be able to start sending refugees back to Turkey from March 20, 2016, the government said, as the country struggles to implement a key deal aimed at easing Europe's migrant crisis. The numbers are daunting: officials said as of Saturday there were 47,500 migrants in Greece, including 8,200 on the islands and 10,500 massed at the Idomeni camp on the Macedonian border. (Photo by Andrej Isakovic/AFP Photo)

A woman and her dogs stop and look at a store mannequin wearing a dog's head mask outside a fashion shop in Nice, France, May 3, 2016. (Photo by Eric Gaillard/Reuters)

A sloth peeks out from behind a door on a floating house in the “Lago do Janauari” near Manaus, Brazil, Tuesday, May 20, 2014. Manaus is one of the host cities for the 2014 World Cup in Brazil. (Photo by Felipe Dana/AP Photo)

Dancers from the British theater company Motionhouse perform a show with excavators entitled “Traction” on the Prado beach in Marseille, France, on May 10, 2013. (Photo by Boris Horvat/AFP Photo)

Men dressed as soldiers pose with models before the opening of the Gamescom 2013 fair in Cologne,Germany, on August 23, 2013. The Gamescom convention is Europe's largest video games trade fair. (Photo by Ina Fassbender/Reuters)