Stunning silhouettes under European cities reveal the size and splendor of the continent’s urban foundations. Photographer and content-manager Anna Arinova, 28, from Moscow, captured the awe-inspiring labyrinths in Russia and Germany. Here: Regenwurmlager, Poland. The Regenwurmlager is an extensive underground fortification area constructed by Germany in 1920s-1940s, now in western Poland, near the city of Międzyrzecz. (Photo by Anna Arinova/Caters News)

With its huge eyes, comical name and diminutive size, Mark R. Smith’s image of a baby Hawaiian bobtail squid can’t help but raise a smile. A curiously endearing creature, the cephalopod is just 1.5cm across, its mantle cavity bearing more than a passing resemblance to a rather natty shower cap. But it is also a beautiful example of symbiosis – nature’s version of “I’ll scratch your back if you scratch mine” – for on the underside of the squid is a light organ which houses bioluminescent bacteria. The squid offers the bacteria protection and food, while the bacteria emit a glow – a handy trait that the squid uses to offset its silhouette, helping it to evade predators in the depths below. Mark R. Smith’s entry combines several images of a Hawaiian bobtail squid with different focus lengths to create a final picture with greater depth of field than normal. (Photo by Mark R. Smith/Wellcome Images/Macroscopic Solutions)

“Ary Borges and his family live in southern Brazil like most families the Borges' love animals and have an array of cats living in their home. The only difference between the cats owned by the Borges family and the cat that is cuddled up on your lap as you read this is the Borges' cats weigh over 700 pounds and could kill you just as soon as look at you. The Borges family shares their home with nine tigers, two lionesses, a chimp and a Chihuahua”. – Amanda Schiavo via Latin Times. Photo: The Borges' family pet dog, Little, is placed on the back of Tom, their tiger, for a photo to be taken, in Maringa, Brazil, Friday, September 27, 2013. (Photo by Renata Brito/AP Photo)

These images show off some of the world's most majestic creatures silhouetted against the beautiful rising and setting sun. The vibrant pictures feature a variety of animals in the wild and were taken by a host of photographers at locations around the world. The striking images all have one thing in common: the photographers' awe-inspiring ability to perfectly capture the silhouettes of earth's beautiful creatures. Here: a blue wildebeest moves through grassland at dawn with the sun in the background in Mara Naboisho Conservancy, Kenya, Africa. (Photo by Renato Granieri/Caters News/Ardea)

Artwork by Ruth Bellotti & Steve Rosewell called “Soldier Scale 1:1” is seen at the 2008 Sculpture by the Sea launch at Mark's Park, Bondi on October 15, 2008 in Sydney, Australia. (Photo by Gaye Gerard/Getty Images)

Lady Gaga arrives at Nevermind Nightclub on July 11, 2011 in Sydney, Australia. Lady Gaga fans gathered outside two Sydney nightclubs in hopes to catch a glimpse of the singer after she sent a cryptic tweet suggesting her she'd be stopping by the venues. (Photo by Marianna Massey/Getty Images)

People purchase the book “Steve Jobs” by Walter Isaacson on launch day at Shanghai's City of Books on October 24, 2011 in Shanghai, China. The book was launched in 30 book cities at the same time across the country. (Photo by ChinaFotoPress/Getty Images)