Great Smoky Mountainspart of the Appalachian system, on the N.C.–Tenn. border; highest range E of the Mississippi and one of the oldest uplands on earth. The mountains are named for the smokelike haze that envelops them. More than 25 peaks rise over 6,000 ft (1,829 m); Clingmans Dome, 6,642 ft (2,024 m), and Mt. Guyot, 6,621 ft (2,018 m), the highest points in Tennessee, were named after geologists T. L. Clingman and Arnold Guyot, who explored the mountains in the late 1800s. The Great Smokies are noted for their many species of trees and a great variety of flowering plants. Nearly 40% of the forest is virgin growth. Black bears are among the most well-known of the many animals and birds in the Great Smokies. Although the region's coves and valleys have been settled since pioneer times, they remained isolated and inaccessible until the 20th cent., when loggers began harvesting the virgin forest and significant tourism led to development of the area, such as the construction of scenic auto and hiking roads and routes. Increased industrialization in the surrounding states and acid rain there have caused vegetation damage and resulted in environmental protection and awareness efforts. Great Smoky Mountains National Park (521,621 acres/211,183 hectares) straddles the crest of the Great Smokies for 71 mi (114 km). The park includes c.600 mi (965 km) of trails through luxuriant forests (the Appalachian Trail follows the crest) and many streams and waterfalls. A number of former farmsteads with log cabins and barns and a grist mill have been preserved. Several museums are there. The park was authorized in 1926 and established in 1930.