From crumbling barns, to abandoned mills, to old general stores, New Hampshire's Preservation Alliance is celebrating 20 years of protecting historic places across New Hampshire. Today on "The Exchange", we’ll look at what started this movement, how its changed, and what challenges it faces as it moves forward. Laura is joined by Jennifer Goodman, Executive Director of the New Hampshire Preservation Alliance and Van McLeod, Commissioner of the New Hampshire Department of Cultural Resources.