The marijuana economy in California, battling obesity in Oklahoma City, the real underground in London, plus buildings that used to be Pizza Huts, and much more, all in this week's urban reads.

  • Colorado may have just legalized pot, but California has nurtured a thriving industry for years. A peek inside the state's weed economy [Next City]
  • How Oklahoma City's mayor inspired the city to collectively lose one million pounds [TED]
  • Used to Be a Pizza Hut is a collection of buildings that—yep, you guessed it!—used to be Pizza Huts [Used to Be a Pizza Hut via Digg]
  • Parts of the London Underground were tunneled, blasted, picked, and drilled through a labyrinth of plague pits and cemeteries [Gizmodo]
  • Valencia, Spain sues Santiago Calatrava for designing an opera house that's falling apart [designboom]
  • Policing housing projects comes with its own dangerous set of risks [New York Times]
  • Will Apple lose talent by locating its spaceship headquarters in suburban Silicon Valley? [Wired]
  • Why here? An investigation into how small cities have found economic success by becoming places where people want to live and work [The Atlantic]
  • A video look back at NYC's outgoing transportation commissioner Janette Sadik-Khan and her legacy of bike and pedestrian improvements for the city [Streetsfilms]
  • What if you had to register your bike, take a safety class, and apply for a rider's license? Should cities tax cyclists? [Forbes]

Opening image courtesy of Geoff George—who you should be following on Instagram. Got an Instagram of your own you'd like us to use in our next link round-up? Tag it #gizmodocities and we'll be in touch if we want to post.