A window cleaner passes a lighter to his colleague while rappelling from a new building in Tianjin March 23, 2007. (Photo by Reuters/Stringer)

The blue-footed booby (Sula nebouxii) is a marine bird in the family Sulidae, which includes ten species of long-winged seabirds. Blue-footed boobies belong to the genus Sula, which comprises six species of boobies. It is easily recognizable by its distinctive bright blue feet, which is a sexually selected trait. Males display their feet in an elaborate mating ritual by lifting their feet up and down while strutting before the female.

German field telegraph operators at work in Warsaw. (Photo by Hulton Archive/Getty Images). 1st October 1914

Father Christmas hands out presents to children at the Aid And Adoption Society home at Leytonstone. (Photo by Gerry Cranham/Fox Photos/Getty Images). 7th December 1938

Crashed cars in Finchley Road, north London. (Photo by Hulton Archive/Getty Images). May 1924

A dog and its owner perform a routine in the main arena on Day three of Crufts at the Birmingham NEC Arena on March 10, 2012 in Birmingham, England. (Photo by Dan Kitwood/Getty Images)

This picture taken on November 1, 2014 shows Japanese body-painting artist Hikaru Cho (L) adding the finishing touches to a body painting of fingers sticking out from prison cell bars on the head of Ryonosuke Tanaka during “Tokyo Designers Week” in Tokyo. Cho, 21, was born to Chinese parents in Japan and burst onto Tokyo's art scene when she entered the city's Musashino Art University in 2012. Cho's ultimate ambition is to paint an entire – and naked – body. (Photo by Yoshikazu Tsuno/AFP Photo)

Germany, Business couple making love under desk. (Photo by Roman Maerzinger/Getty Images)