Catherine, Duchess of Cambridge speaks to soldiers as she arrives at Calgary Airport on July 7, 2011 in Calgary, Canada. (Photo by Chris Jackson/Getty Images)

“An egg case or egg capsule, colloquially known as a mermaid's purse or devil's purse, is a casing that surrounds the fertilized eggs of some sharks, skates, and chimaeras”. – Wikipedia. Photo: OBX Skate (Raja eglanteria) Egg Case – Mermaid's Purse. (Photo by altereye1)

A visitor looks at a sculpture entitled “Couple Under an Umbrella, 2013” by artist Ron Mueck during the press day for his exhibition at the Fondation Cartier pour l'art contemporain in Paris April 15, 2013. (Photo by Charles Platiau/Reuters)

A tourist poses for a picture with the Sphinx at the Pyramids of Giza in Cairo, Egypt, on October 19, 2011. (Reuters/Jamal Saidi)

Captain George Ash lies on his back as he prepares to shoot the bowl from the clay pipe held between a blindfolded corporal's teeth. (Photo by Fox Photos/Getty Images). 18th April 1932

(L-R) Michael Kasrpowicz, Jason Gillespie, Brett Lee and Glenn McGrath of Australia re-enact the famous Beatles album cover at Abbey Road on July 19, 2005 in London, United Kingdom (Photo by Hamish Blair/Getty Images)

A young boy adjusts his friend's Adolf Hitler mask during a game on a street in King's Cross, London. (Photo by William Vanderson/Getty Images). 1938