British artist, Mark Coreth sits on top of the “Sydney Ice Bear” carved from a 10 tonne block of ice to illustrate how humans affect climate change in the Arctic at Customs House on June 3, 2011 in Sydney, Australia. The public will be welcomed to touch the bear, and leave an imprint which will begin the melting process and act as a metaphor for how humans affect the environment. The ice bear's has visited six cities on it's global tour since 2009; the visit to Sydney coincides with World Environment Day on June 5. (Photo by Lisa Maree Williams/Getty Images)

Inmates sleep on the steps of a ladder inside the Quezon City jail at night in Manila in this picture taken on July 21, 2016. There are 3,800 inmates at the jail, which was built six decades ago to house 800, and they engage in a relentless contest for space. Men take turns to sleep on the cracked cement floor of an open-air basketball court, the steps of staircases, underneath beds and hammocks made out of old blankets. (Photo by Noel Celis/AFP Photo)

In this November 2, 2017 photo, Mathew Fulkerson and his wife Leigh Ann pose at their Subterra Airbnb located in a former underground missile silo base near Eskridge, Kan. It was designed to house a nuclear warhead six decades ago – but now, this Cold War silo is the perfect spot for a mini break at just $133 a night. (Photo by Thad Allton/The Topeka Capital-Journal via AP Photo)

Photochromes are vibrant and nuanced prints hand-coloured from black-and-white negatives. Created using a process pioneered in the 1880s, these images offer a fascinating insight into the world when colour photography was still in its infancy. A Tour of the World in Photochromes is at the Swiss Camera Museum, Vevey, until 21 August. Here: Street food in the Strada del Porto in Naples, Italy, 1899. (Photo by Swiss Camera Museum/The Guardian)

A spider monkey eats a mango at the Paraguana zoo in Punto Fijo, Venezuela July 22, 2016. Some 50 animals have starved to death in the last six months at one of Venezuela's main zoos due to chronic food shortages that have plagued the crisis-stricken South American nation. (Photo by Carlos Jasso/Reuters)

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.