A Virgin Atlantic passenger plane flies in the sky with the moon seen in the background, in London, Britain January 19, 2016. (Photo by Toby Melville/Reuters)

A man is silhouetted in front of the Allianz-Arena as he walks his dogs at sunrise in Munich, southern Germany, Friday, April 10, 2015. (Photo by Peter Kneffel/AP Photo/DPA)

A visitor holds up her toy bunny to the aquarium glass in front of Aurora the Russian polar bear at the Sao Paulo Aquarium in Sao Paulo, Brazil, Thursday, April 16, 2015. (Photo by Andre Penner/AP Photo)

A photographer has done her best to guess what her dog is daydreaming about – creating a series of fantasy adventures around her unaware pooch as he takes his daily naps. (Photo by Caters News)

HRP-4C, a five-foot humanoid robot developed at Japan's National Institute of Advanced Industrial Science and Technology, sings and dances with performers at the Digital Contents Expo in Tokyo on October 17, 2010. The robot runs entertainment software called Choreonoid, a name formed from the words “choreograph” and “humanoid”. (Yoshikazu Tsuno/AFP)

German flying ace Baron Manfred von Richthofen (1892–1918) also known as The Red Baron with his dog Moritz, circa 1916.

Ginger Stanley performs a grand jete during her solo underwater ballet at Silver Springs, Florida. (Photo by Bruce Mozert/Three Lions/Getty Images). Circa 1956