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)

A reveller wearing a costume dances as she holds a dring during the carnival street parade in Valletta, Malta, February 25, 2017. (Photo by Darrin Zammit Lupi/Reuters)

A passenger (C) climbs through the window of an overcrowded bus as limited public transportation operates in the city during the ongoing fuel crisis in Kathmandu, Nepal October 9, 2015. Nepal is considering air-lifting fuel, possibly from Bangladesh, as supply routes from India stay blocked by protesters opposing its new constitution, a short-term solution ahead of a key festival even as the government talks to China for help. (Photo by Navesh Chitrakar/Reuters)

Clouds float over an open field January 3, 2007 in Shirley Heights, Antigua. (Photo by Joe Raedle/Getty Images)

O Santa Claus of Australia competes in the mens 80–84 years 100 metres heats during day two of the 2009 Sydney World Masters Games at Sydney Olympic Park on October 11, 2009 in Sydney, Australia. (Photo by Mark Nolan/Getty Images)

“The Antonov An-124 Ruslan (NATO reporting name: Condor) is a strategic airlift jet aircraft. It was designed by the Soviet Union's Antonov design bureau. It is the world's largest ever serially-manufactured cargo airplane and world's second largest operating cargo aircraft. During development it was known as Izdeliye 400 in house, and An-40 in the West. First flown in 1982, civil certification was issued on 30 December 1992”. – Wikipedia

Photo: The new metro called “Bombardier MOVIA” with 22,50 meters long and 3,2 meters wide is load on a Antonow An-124 plane for transport to India on February 25, 2009 in Parchim, Germany. (Photo Handout Bombardier Transportation via Getty Images)

“The scientists behind NASA's $2.5 billion Curiosity rover mission on Mars on Tuesday explained the nature of a tiny, gleaming "flower" embedded in Red Planet rock, and revealed where they'll be using the SUV-sized robot's drill for the first time”. – Alan Boyle via NBCNews.com

Photo: Scientists say that a “Martian flower”, seen here in an image from the Curiosity rover's Mars Hand Lens Imager, is a 2-millimeter-wide grain or pebble that's embedded in the surrounding rock. Another, darker-colored mineral grain can be seen above and to the left. (Photo by NASA)

Maria, 18, wearing a traditional Sevillana outfit, poses for a portrait during the traditional Feria de Abril (April fair) in the Andalusian capital of Seville April 16, 2013. (Photo by Marcelo del Pozo/Reuters)