A participant runs on stairs during a vertical run event at China World Summit Wing hotel in Beijing, China, September 19, 2015. About 800 runners took part in the event on Saturday, which takes runners up 82 floors, covering a total of 2,041 steps to a height of 330 metres, the organizer said. (Photo by Kim Kyung-Hoon/Reuters)

Participants stretch their bodies as they pose for pictures before the Beijing International Marathon in Beijing, China, September 20, 2015. About 30,000 runners participated in the annual running event. (Photo by Kim Kyung-Hoon/Reuters)

This picture taken on February 23, 2014 shows participants wearing dresses running half-naked in the annual 3.5 km Undie Run held in the Olympic Forest Park smog-covered Beijing. Some 200 participants took part in this event, many of them with gas masks, as dangerous smog blighted swathes of northern China in recent days. (Photo by AFP Photo/STR)

Actors wrapped in blankets react at the set of the post-apocalyptic movie “Zombie Era” at an abandoned factory complex in Langfang, Hebei province, China December 16, 2016. (Photo by Damir Sagolj/Reuters)

A model performs on the Toyota FV2 concept car during the 2014 Beijing International Automotive Exhibition at China International Exhibition Center on April 21, 2014 in Beijing, China. More than 2,000 automotive enterprises from 14 countries and regions participated in the 2014 Beijing International Automotive Exhibition from April 20 to April 29. (Photo by Feng Li/Getty Images)

A dramatic rise in owning exotic pets in China is fuelling global demand for threatened species. The growing trade in alligators, snakes, monkeys, crocodiles and spiders is directly linked to species loss in some of the world’s most threatened ecosystems. Here: A fennec fox (Vulpes zerda) is groomed in a pet store in central Beijing. Native to the Sahara in North Africa, the species became a popular pet after being depicted as a character in Disney’s 2016 animated movie Zootopia. Individuals can cost between $2,000–$3,000. (Photo by Sean Gallagher/The Guardian)

Participants run at the “Half-Naked Marathon” at Olympic Forest park in Beijing, China, February 28, 2016. This annual running event which requires participants to run half-naked, was organized to promote environmentally friendly lifestyles. (Photo by Kim Kyung-Hoon/Reuters)

The sun catches on the panels of a 1928 Rolls Royce Phantom at Northington Grange, the summer home of the Grange Park Opera, on April 16, 2011 near Winchester, England. The English Heritage Grade 1 listed Greek Revival style property was the setting for the inter-war Rolls Royce20-Ghost Club members which was founded in 1949 by a group of owners of vintage Rolls Royce cars. (Photo by Matt Cardy/Getty Images)