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.

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

Aymara witchdoctor Ricardo Quispe, also called “Lord of the Lake”, throws coca leaves during a ritual to predict the future, at the witches market of El Alto, on the outskirts of La Paz, December 31, 2014. Dozens of witch doctors tend to a warren of stalls in El Alto, making offerings to give thanks, to promise luck at work or in love, or to call up spirits and banish curses at the end of the year. (Photo by David Mercado/Reuters)

Bulgarian men dance in the icy waters of the Tundzha river during a celebration to commemorate Epiphany Day in the town of Kalofer January 6, 2015. It is believed that the ritual will bring good health to the participants throughout the new year. (Photo by Stoyan Nenov/Reuters)

Palestinian Munir Shindi, 36, drives a replica of a 1927 Mercedes Gazelle that he built from scratch, on a street in Gaza City June 19, 2016. (Photo by Mohammed Salem/Reuters)

A period of relative stability has put the Iranian capital No1 on the list of world cities that have achieved biggest improvements in liveability over the past five years, as calculated by the Economist Intelligence Unit. The “most improved” top 10 contains some unexpected names. So, eg, the fourth place: Abidjan, Ivory Coast. Latest ranking: 128; Ranking five years ago: 131; Five-year index movement: 3.8%. Here: A supporter of Ivory Coast president Alassane Ouattara campaigns in a market in the city’s Koumassi quarter. (Photo by Sia Kambou/AFP Photo)

Relatives clean the body of Paul Sampe Lumba who has been dead for seven yeas during the Ma'nene ritual at Panggala Village on August 26, 2016 in Toraja, Indonesia. The Ma'nene ritual in performed during a ceremony every three years, where the dead are exhumed for a change of clothes, among the people of Toraja as an expression of the love of the surviving family. (Photo by Sijori Images/Barcroft Images)

A couple dance tango for tourists at Caminito, a touristic hotspot of La Boca neighborhood in Buenos Aires, Argentina, October 15, 2016. (Photo by Enrique Marcarian/Reuters)