“Cassowaries are large, flightless birds related to emus and (more distantly) to ostriches, rheas, and kiwis”, writes Olivia Judson in the September issue of National Geographic magazine. How large? People-size: Adult males stand well over five foot five and top 110 pounds. Females are even taller, and can weigh more than 160 pounds. Dangerous when roused, they’re shy and peaceable when left alone. But even birds this big and tough are prey to habitat loss. The dense New Guinea and Australia rain forests where they live have dwindled. Today cassowaries might number 1,500 to 2,000. And because they help shape those same forests – by moving seeds from one place to another – “if they vanish”, Judson writes, “the structure of the forest would gradually change” too. (Photo by Christian Ziegler/National Geographic)

Ukrainian state emblem is seen on a gun's holster as soldiers guard naval base in the village of Novoozernoye, some 91 km west of Crimean capital Simferopol, Ukraine, on Monday, March 3, 2014. Ukraine says Russian forces controlling the strategic region of Crimea are demanding that the crew of two Ukrainian warships in Sevastopol's harbor must surrender. (Photo by Ivan Sekretarev/AP Photo)

“Lobsang and 66 fellow monks were imprisoned in 1959. When released 21 years later, he was one of only three survivors. While in prison his best friend, a rinpoche, died in his arms. Tensin was later discovered to be the reincarnation of that friend. Lobsang said there are so many characteristics of his old friend in the young boy”. (Photo and caption by Phil Borges)

The disused bobsled track from the Sarajevo 1984 Winter Olympics is seen on Mount Trebevic, near Sarajevo, September 19, 2013. Abandoned and left to crumble into oblivion, most of the 1984 Winter Olympic venues in Bosnia's capital Sarajevo have been reduced to rubble by neglect as much as the 1990s conflict that tore apart the former Yugoslavia. (Photo by Dado Ruvic/Reuters)

Russia's Darya Klishina prepares for the women's long jump qualification during the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Tuesday, August 16, 2016. She might be feeling the pressure of being all alone, but Darya Klishina could yet still win Russia's only athletics medal at the Rio 2016 Games. (Photo by Matt Dunham/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)

Vets of Animals Asia Foundation's Vietnam Bear Rescue Center hold a paw of a sun bear as they check its health while it is rescued from a Vietnamese family in Nam Dinh province, south of Hanoi, Vietnam August 18, 2016. A man in northern Vietnam has voluntarily handed over a bear his family had caged for seven years to an animal rights organization, which will take it to a nearby sanctuary. (Photo by Reuters/Kham)

A young man looks over his shoulder as men watching a soccer match in a nearby bar ask why he isn't watching the game, while walking with his date during the men's gold medal soccer match between Brazil and Germany during Rio 2016 on Saturday, August 20, 2016. (Photo by Aaron Ontiveroz/The Denver Post)