Coloured X-ray of a barn owl. A physicist has used X-ray to create an extraordinary collection of artwork. Arie van't Riets pictures reveal birds, fish, monkeys and flowers in an incredible new light. The 66-year-old, from Bathmen in the Netherlands, began X-raying flowers as a means to teach radiographers and physicians how the machine worked. But after adding a bit of colour to the pictures, the retired medical physicist realised the potential for an exciting new collection of art. (Photo by Arie van't Riet/Barcroft Media)

The X-47B prototype on Tuesday flew off an aircraft carrier and into the history books. Today's achievement, the first-ever catapult launch of an unmanned aircraft from the flight deck of a carrier, promises to open up a new chapter in the annals of naval aviation. Photo: An X-47B pilot-less drone combat aircraft is launched for the first time off an aircraft carrier, the USS George H. W. Bush, in the Atlantic Ocean off the coast of Virginia, May 14, 2013. The U.S. Navy made aviation history on Tuesday by catapulting an unmanned jet off an aircraft carrier for the first time, testing a long-range, stealthy, bat-winged plane that represents a jump forward in drone technology. (Photo by Jason Reed/Reuters)

Australian photographer Brendan Fitzpatrick’s X-ray photographs expose the inner workings of toys. Fitzpatrick’s photographs are both whimsical and mechanical, evoking the curiosity of childhood and the desire to discover how things look and work from other perspectives. The strategic placement of wires, batteries, and screws are revealed, the complexity of the inside contrasting with the seemingly simplistic design of the outside. Fitzpatrick uses chest X-ray and mammogram machines to photograph flowers, toys, and creatures, then enhances the color in the images in order to more effectively distinguish the various parts that have been exposed. This photographs are part of series he calls “Invisible Light”. (Photo by Brendan Fitzpatrick)

These adorable cats – which are twins – showcase their contrasting blue and green eyes. The cats have a condition called heterochromia iridis, which causes each eye to vary in color. (Photo by @sis.twins/Caters News Agency)

Snoopy the Cat (大肥猫宝儿) is one of the most popular cats in the world especially in China. She is an Exotic Shorthair cat with a lovely master that takes pictures of her everyday.

A little girl hangs three Siamese kittens on a washing line in a garden in Croydon, London. (Photo by Fox Photos/Getty Images). 14th July 1931

If Kim Kardashian was a feline shed be purr-fect for this new book which features a collection the worlds best cat “selfies”. The furry frames have been compiled by cat owner Charlie Ellis who has scoured the globe for the perfect puss pictures. In his book “Cat Selfies” moggies try their hand at the craze most of their humans have become addicted to posting on social media. And it turns out cats might be better at taking photos than their owners with a variety of poses captioned in the book. (Photo by Charlie Ellis/Caters News)