Popocatepetl volcano spews incandescent material as seen from Paso de Cortés on May 23, 2023 in Amecameca, Mexico. The second highest volcano in the country increased its activity while Mexican authorities raised the alert to yellow phase 3. Popocatepetl volcano caused the fall of ashes in different municipalities in Puebla, Estado de Mexico and Mexico City. Mexican army has spread forces as a preventive measure while the 3 levels of government are in coordination to observe the activity of the volcano and the situation in the surroundings. (Photo by Cristopher Rogel Blanquet/Getty Images)

It’s time to start watching for Comet PANSTARRS, one of two comets to get excited about in 2013. Photo: This image provided by NASA shoaws the comet PANSTARRS as seen from Mount Dale, Western Australia on March 5, 2013. According to NASA on March 10, it will make its closest approach to the sun about 28 million miles (45 million kilometers) away. As it continues its nightly trek across the sky, the comet may get lost in the sun's glare but should return and be visible to the naked eye by March 12. (Photo by AP Photo/NASA)

Rock and roll musician Elvis Presley during a press conference after his first performance at the International Hotel in Las vegas, Nevada on August 1, 1969. (Photo by Michael Ochs Archives/Getty Images)

Mercedes Formula One driver Lewis Hamilton of Britain sprays champagne at a grid girl as he celebrates his victory on the podium after the Chinese F1 Grand Prix at the Shanghai International Circuit, April 12, 2015. (Photo by Carlos Barria/Reuters)

Ex-Pussycat Dolls singer Nicole Scherzinger and The Cuban Brothers perform at the de Grisogono party during the 71st annual Cannes Film Festival at Villa des Oliviers on May 15, 2018 in Cap d'Antibes, France. (Photo by Goff Photos)

A performer takes part in the annual street parade, which is part of the Carnival of Cultures celebrating the multi-ethnic diversity of the city, in Berlin, Germany on May 20, 2018. (Photo by Hannibal Hanschke/Reuters)

View of the Villarrica volcano taken from Pucon, some 800 kilometres south of Santiago, showing signs of activity on December 06, 2017. (Photo by Christian Miranda/AFP 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)