A dying Californian shopping mall gets the world's largest green roof

City links: Greening Silicon Valley, Guatemala City's mystery zone and spray paint cycle safety in Berlin feature in this week's best city stories

This week's best city stories from around the web explore Silicon Valley's newest sustainability project, an app which automatically sprays potholes you cycle over, the "missing" Guatemala City neighbourhood and Indianapolis' growing pains with a new electric car share scheme.

We'd love to hear your responses to these stories, and any others you've read recently, both on Guardian Cities and elsewhere. Just share your thoughts in the comments below.