There's a place -- in the heart of Denver -- where injection drug users pick up clean needles and drop off dirty ones. It's blocks away from the state Capitol, where lawmakers will continue to wrestle with Colorado's drug epidemic. At this center, people also learn how to avoid overdosing -- and keep their veins healthy. And, Ian Thompson lives in Colorado, but when Prince William married Kate Middleton in England almost seven years ago, he was right on the altar as a verger.