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.

Blue Marlin is a semi-submersible heavy lift ship from Dockwise Shipping of the Netherlands. Designed to transport very large semi-submersible drilling rigs above the transport ship's deck, it is equipped with 38 cabins to accommodate 60 people, a workout room, sauna and swimming facilities. Blue Marlin and her sister ship MV Black Marlin comprise the Marlin class of heavy lift ship.

Chantel Sydnor participates in the annual Sturgis Motorcycle Rally in Sturgis, South Dakota, August 4, 2015. This year marks the 75th anniversary of the rally expected to draw hundreds of thousands of motorcycle enthusiasts from around the world for events throughout the week-long festival, according to organizers. (Photo by Kristina Barker/Reuters)

The Taiwan Blue Magpie (Urocissa caerulea), also called the Taiwan Magpie or Formosan Blue Magpie, is a member of the Crow family. It is an endemic species living in the mountains of Taiwan at elevations of 300 to 1200m.

Seen in a long exposure nighttime photograph, a burned van rests in a lot while a wildfire glows on the horizon in Phelan, Calif., early Thursday, August 18, 2016 2016. (Photo by Noah Berger/AP Photo)

These are the ambitious plans which suggest skyscrapers of the future may house an entire city. The Endless City project is an award-winning proposal by sure Architecture, who propose turning skyscrapers into complete ecosystems. London is the proposed city for the mixed-use tower – which would feature huge ramps linking different sections of the structure. The company, whose design won the SkyScrapers and SuperSkyScrapers Competition, insist the structure would be a great space-saver in dense cities which have previously spread outwards rather than upwards. (Photo by Caters News)

A man sleeps between tombstones in front of his single-room home on a hot night in the Cairo Necropolis, Egypt, October 13, 2015. In the sprawling Cairo Necropolis, known as the City of the Dead, life and death are side by side. Amid a housing crisis in Egypt, and with the population of greater Cairo estimated at about 20 million, people count themselves lucky to have a place to call home in the graveyards that date back hundreds of years. (Photo by Asmaa Waguih/Reuters)

Kale grows at Kajodlingen farm in Gothenburg, Sweden, September 28, 2016. They are doing it on the rooftops, on tower block balconies and even on a disused railway: Swedes have discovered a passion for urban gardening as a way of growing fresh food and getting back in touch with nature. Part of a global movement, an increasing number of Swedish city-dwellers are growing their own in window boxes and allotments or are visiting public gardens built in or on industrial or office spaces. (Photo by Maxim Shemetov/Reuters)