Kaltura
Located near Bowling Green, Kentucky, Mammoth Cave is the longest underground cave system in the world; over three hundred miles of explored passageways. In the area known as "Gothic Avenue," visitors in the 1800's wrote their names in candle smoke, so that they would never be forgotten.
Nitrates mined from Mammoth Cave were used to make sixty percent of the gunpowder used by the U.S. during the War of 1812.
