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

In this Wednesday, August 20, 2014 photo released by Red Bull, Maikel Melero of Spain warms up prior to the fifth stage of the Red Bull X-Fighters World Tour in the South African savanna of Pretoria, South Africa. (Photo by Joerg Mitter/AP Photo/Red Bull)

In this May 17, 2015, photo, two men walk past pagodas at Ngwe Saung beach, Pathein township, about 145 miles from Yangon, Myanmar. (Photo by Khin Maung Win/AP Photo)

A gravedigger competes as a boy looks on during the first National Grave Digging competition at the public cemetery of Debrecen, 226 km east of Budapest, Hungary, Friday, June 3, 2016. Eighteen two-man teams of Hungarian gravediggers are demonstrating their skills for a place in a regional championship to be held in Slovakia. (Photo by Zsolt Czegledi/MTI via AP Photo)

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)

An armed youth loyal to the Houthi movement takes part in a protest against the Saudi-backed exiled government deciding to cut off the Yemeni central bank from the outside world, in the capital Sanaa, Yemen August 25, 2016. (Photo by Mohamed al-Sayaghi/Reuters)

This Wednesday, August 31, 2016 photo, provided by the Syrian anti-government activist group Aleppo Media Center (AMC), shows Syrian boys dive into a hole filled with water that was caused by a missile attack in the rebel-held neighborhood of Sheikh Saeed in Aleppo province, Syria. (Photo by Aleppo Media Center via AP Photo)

Waldo, a 6-year-old Tibetan Terrier belonging to Susan and Mike Leverette of Sebastian, competes in the third heat of the medium dogs division at the Hang 20 Surf Dog Classic at Carlin Park in Jupiter Saturday, August 29, 2015. “The waves are a little bigger than we are used to”, said Susan. (Photo by Bruce R. Bennett/The Palm Beach Post)