Tennessee is known as the Volunteer State, but its fascinating history goes well beyond the name. It holds major records for subterranean wonders, iconic beverages, and world-renowned musical broadcasting. It hosts the world’s longest-running live radio show: Broadcasting every weekend since 1925, Nashville’s The Grand Ole Opry is the longest-running live radio program in global history. It has hosted and launched the careers of generations of country music legendsIt has the country’s largest underground lake: Located in Sweetwater inside the Craighead Caverns, The Lost Sea is recognized as the largest non-subglacial underground lake in the United States. Guided tours let visitors explore its massive chambers and take glass-bottom boat trips on its crystal-clear waters. Mountain Dew was invented in Knoxville: Originally created in the 1930s by beverage bottlers Barney and Ally Hartman, this now-famous soft drink was intended as a mixer for whiskey.