Mountain Dew is a soft drink manufactured and distributed by PepsiCo. The main formula was invented in Knoxville, Tennessee, named and first marketed in Knoxville and Johnson City, TN in the 1940s, then by Barney and Ally Hartman, in Fayetteville, North Carolina and across the United States in 1964. Between the 1940s and 1980s, there was just one variety of Mountain Dew, which was citrus-flavored and caffeinated in most markets. Diet Mountain Dew was introduced in 1988. When removed from its characteristic green bottle, the original Mountain Dew is bright yellow-green and translucent.