East Tennessee is both geographically and culturally part of Appalachia, and has been included— along with Western North Carolina, North Georgia, Eastern Kentucky, Southwest Virginia, and the state of West Virginia— in every major definition of the Appalachian region since the early 20th century. East Tennessee is home to the nation's most visited national park— the Great Smoky Mountains National Park— and hundreds of smaller recreational areas. East Tennessee is often called the birthplace of country music, due largely to the 1927 Victor recording sessions in Bristol, and throughout the 20th and 21st centuries has produced a steady stream of musicians of national and international fame. Oak Ridge was the site of the world's first successful uranium enrichment operations which paved the way for the atomic age. The Tennessee Valley Authority, created to spur economic development and help modernize the region's economy and society, has its administrative operations headquartered in Knoxville and its power operations headquartered in Chattanooga.