By Kim Grant, Colorado Preservation, Inc. Are there really tunnels under downtown buildings in Colorado’s towns? Where do the open staircase entrances in front of many downtown businesses lead to? What kind of businesses occupied these spaces? To find answers to many of these questions and highlight these unique historic resources, Colorado Preservation Inc. listed “Downtown Underground” as a statewide historic resource worthy of protection on Colorado’s Most Endangered Places list in 2018. These once common, but rapidly disappearing features, of many downtowns across the state of Colorado include the underground entrances to the lower levels of historic commercial buildings, ...