Denali National Park and Preserve (Alaska) is six million acres of wild land, bisected by one ribbon of road. Travelers along it see the relatively low-elevation taiga forest give way to high alpine tundra and snowy mountains, culminating in North America’s tallest peak, Mount McKinley – which is still growing at about 1 millimeter per year. Wild animals large and small roam unfenced lands, living as they have for ages. Photo of a bear digging in front of Mount McKinley by Daniel A. Leifheit, National Park Service.