Although trained as a physician, I have explored ‘hidden areas’ often out of the sight of most people. Some of these are physical places including prisons, refugee camps, and hospital wards housing children with nowhere else to live. Others are simply hidden because they haven’t risen to visibility in the public’s eye yet. Examples include the rise of adolescent HIV in the AIDS epidemic, or the need for identifying a set of core skills needed by humanitarian assistance workers, regardless of their professional training.