>> they had done the grounds up beautifully and you heard birds everywhere. all you could hear were the sounds of birds, birds, birds, birds. that was very surprising to me. you couldn't escape it. >> the prison's garden-like grounds and collection of birds, including peacocks, are part of a renovation project. prison officials felt a relaxing natural environment could help their rehabilitation efforts. >> it did actually have a calmer feel than i expected. the buildup was pretty big. serbia's biggest, most notorious prison, then here i am with peacocks and birds and cats wandering around. >> in fact, when we wandered into the prison's shoe factory where inmate workers make dozens of shoes per day, the scene was more reminiscent of a disney film than a prison. >> this is our pet. >> this shoe shop was a pretty unique area that we got to film in.