A young arab boy, armed with a rifle and a knife, in the Aden Protectorate near Yemen. (Photo by Richards/Fox Photos/Getty Images). February 1938

A young exhibitor arrives with her kitten on a lead at the National Cat Club show at Crystal Palace, London. (Photo by Fox Photos/Getty Images). 2nd December 1931

Waura Indians wrestle during this year's “quarup”, a ritual held over several days to honour in death a person of great importance to them, in Xingu National Park, Mato Grosso State, Brazil August 25, 2013. (Photo by Ueslei Marcelino/Reuters)

A Galapagos Tortoise shell is used as a foot rest at Heathrow Airport's Animal Reception Centre on January 25, 2011 in London, England. Many animals pass through the centre's doors ranging from exotic animals such as snow leopards and elephants, snakes and crocodiles, to the more common such as cats and dogs. In 2010 alone the centre processed approximately 10,500 cats and dogs, 1,300 birds, 105,000 day old chicks, 246,000 reptiles, 230 horses and 29 million fish. Most animals are part of zoo transfer schemes, the pet trade, or are pets in transit. (Photo by Dan Kitwood/Getty Images)

The Jumbo Stay blends into the background at Stockholm Arlanda Airport. If you spot it as your plane rolls along a taxiway, you might notice an aging widebody jet parked by its lonesome self in a secluded part of the airport.

The Verreauxs Sifaka, otherwise known as Dancing Sifaka, who was caught strutting its stuff in Madagascar, has definitely learnt a lesson or two from King Julian – from the 2005 film “Madagascar”. Raising both of its arms and lunging from side to side, this lemur definitely likes to move it, move it. (Photo by Shannon Wild/Caters News Agency)

Egyptian bootblacks cleaning a European's shoes in Cairo. (Photo by Hulton Archive/Getty Images). Circa 1870

A member of the German wireless police picks up signals on the radio equipment he carries on his back, while his colleague takes notes. (Photo by General Photographic Agency/Getty Images). Circa 1925