A man is silhouetted as he stands on a walkway in the sky lobby at the Chancellery, the seat of German Chancellor Angela Merkel (not pictured) in Berlin, May 7, 2014. (Photo by Thomas Peter/Reuters)

Fog hangs between pine trees in a forest near Neubrueck, eastern Germany, on November 20, 2012. Meteorologists forecast cloudy sky and temperatures around 5 degrees Celsius for the region. (Photo by Patrick Pleul/AFP Photo)

The setting sun illuminates the sky behind wind turbines of a wind park near Neusiedl am See, December 22, 2014. (Photo by Heinz-Peter Bader/Reuters)

Models turned into “humanoid” robots pose on a train at Waterloo Station on October 2, 2016 in London, England for the launch of new Sky Atlantic TV drama Westworld. (Photo by Matt Alexander/PA Wire)

Fireworks light the sky over Copacabana beach during New Year's Eve celebrations in Rio de Janeiro, Brazil, Thursday, January 1, 2016. (Photo by Mauro Pimentel/AP Photo)

The sky looked on fire this morning, as it made the clouds glow red, just before sunrise at Peterborough Rowing Lake, in Nene Park, UK on January 18, 2017. (Photo by Paul Marriott/Rex Features/Shutterstock)

Backdropped by a night time view of the Earth and the starry sky, the Space Shuttle Endeavour is seen docked to the International Space Station on May 28, 2011. (Photo by Reuters/NASA)

A giant storm cloud can be seen in the sky above swimmers near Mollymook Beach, south of Sydney, March 5, 2014. (Photo by David Gray/Reuters)