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 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)

NFL player Rob Gronkowski, of the New England Patriots, from second left, accepts the best comeback athlete award with his brothers, NFL free agent Chris Gronkowski and former NFL player Dan Gronkowski at the ESPY Awards at the Microsoft Theater on Wednesday, July 15, 2015, in Los Angeles. (Photo by Chris Pizzello/Invision/AP Photo)

Tourists ice skate at night on the Eiffel Tower's skating rink in Paris December 9, 2014. The skating rink, located on the first level of the Eiffel Tower, opens to the public as part of the Christmas holiday season. (Photo by Charles Platiau/Reuters)

Partially demolished houses stand in the Vila Autodromo slum with the Rio 2016 Olympic Park in the background in Rio de Janeiro, Brazil, February 25, 2016. (Photo by Ricardo Moraes/Reuters)

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)

“Old Mursi woman”. Old woman by the huts of her village. Location: Marenke, Omo valley, Ethiopia. (Photo and caption by Jorge Fernandez/National Geographic Traveler Photo Contest)

ATTENTION! All pictures are presented in high resolution. To see Hi-Res images – just TWICE click on any picture. In other words, click small picture – opens the BIG picture. Click BIG picture – opens VERY BIG picture.

A police officer gives instructions to migrants rushing to board a train that would take them towards Serbia, at the railway station in the southern Macedonian town of Gevgelija, Wednesday, August 20, 2015. Macedonian police stepped up the security at the border with Greece apparently trying to stem recent surge of migrants who are coming from Greece. (Photo by Darko Vojinovic/AP Photo)