The Great Smoky Mountains form a major southern Appalachian range along the Tennessee–North Carolina border, within the Blue Ridge province, and are most famous as the heart of Great Smoky Mountains National Park, established in 1934. Named for the fog-like haze over their ridges, the Smokies combine striking height, abundant rainfall, and streams that feed the Tennessee River watershed. They are nationally and internationally significant for biodiversity, old-growth forest, and protected status, including recognition as an International Biosphere Reserve and UNESCO World Heritage Site. The range also preserves deep geological history and evidence of Appalachian communities, despite heavy logging that altered much of the forest in the late 19th and early 20th centuries.