These high-quality images may look like photographs of world cities at night taken by astronauts from the International Space Station – but they are painstakingly constructed from public map data and finessed by artist Marc Khachfe. See more

“Yes, London is an unfriendly city – and long may it stay that way”

Earthquakes, hurricanes, cyclones and tsunamis: the world’s 10 riskiest cities

What are the world’s riskiest cities when it comes to natural disasters? A reinsurance company set out to assess 616 cities around the world for their risk of earthquake, hurricanes and cyclones, storm surge, river flooding and tsunami. See more

Pictured: Victoria harbour in Hong Kong. Photograph: Philippe Lopez/AFP/Getty Images

Royal Mail to open Mail Rail to the public – in pictures

The Post Office underground railway – Mail Rail – ran under the streets of London largely unnoticed for more than three quarters of a century. Since 2003, the electrified railway has been dormant, with just a handful of engineers to maintain it. Under new plans developed by the British Postal Museum & Archive, that could all be about to change. See more

Photos courtesy of BPMA

Nine Chinese cities suffered more days of severe smog than Beijing

Photographs of a smog-wreathed Tiananmen Square and the iconic headquarters of China Central Television dominated reports of Chinese pollution last year, but analysis shows nine other Chinese cities suffered more days of severe smog than the capital in 2013.

The worst was Xingtai, a city of more than 7 million people south-west of Beijing, which was hit by 129 days of “unhealthy air” or worse – the threshold at which pollution is considered at emergency levels – and more than twice as many days as the capital experienced. Read more

Photo: China Stringer Network / Reuters

Urban Instagram photographers you should follow

Guardian Cities recently took over #GuardianCam, showcasing some of the best urban photography from around the world. Check out more urban ‘grammers.

Photographs, top to bottom: garethponregalphis, and siumomomo

I left New York for LA because creativity requires the freedom to fail

New York is about success. Maybe that’s why it’s no longer the world’s cultural capital, writes Moby

Photograph: Larry Brownstein/Photodisc

#GuardianCam lands in San Francisco 

The hills, the bay, the fog and the architecture make it a wonder for photographers. @lec101 tries to look for ethereal, magical moments that feel like refreshing escapes from city life, and says she is “forever mesmerized by the wild fog that is unique to San Francisco”.

Follow @guardiannews on Instagram for more our reporters and contributors around the world 

To celebrate its launch this week, the Guardian Cities team is taking over #guardiancam on Friday. Urban Instagrammers from around the globe will be showcasing some of the best city feeds. 

This photo comes from @p_d_y, a fimmaker capturing daily life in Amsterdam. His favourite spot in the city is the Jordaan district, because “it’s full of the things that make it an amazing city for a photographer: canals, bridges, small streets and historical architecture. It’s what the locals like to call the ‘real’ Amsterdam”. 

Follow @guardiannews on Instagram for more our reporters and contributors around the world 

High Lines and park life: why more green isn’t always greener for cities

Transforming old industrial areas into urban woodland may look nice but can be conterproductive in the long run, says Owen Hatherley

Photographs: Arup (top); Andria Patino/Alamy (bottom).