Bungie Studios, creators of the iconic Halo video game series, turned 20 yesterday. See behind-the-scenes footage and interviews with key personnel in the retrospective documentary above, made by the folks at Bungie themselves.

The Halo games have sold more than 40 million copies worldwide and helped set the template for blockbuster video games over the last decade. Though a fourth title in the series is forthcoming from 343 Industries and Microsoft Studios, Bungie moved on from the Halo universe after last year's Reach. They are currently working on a top-secret new franchise.