Some of the earliest known evidence of humans living in and around southern Arizona and New Mexico has been traced to around 23,000 years ago. University of Arizona archeologist Vance Holliday discusses his finds near White Sands Missile Range and how they add to the book of human history in the region. Vance Holliday spoke with Leslie Tolbert, Ph.D. regent's professor emerita in Neuroscience at the University of Arizona.