Mammoth Cave was cool as in 54° F or 12° C, which is to be expected. Karen and I were on limited schedule of time, because we were heading over to Lexington, Kentucky. Due to our limited time, we decided to only go on the self guided tour of Mammoth Cave. This tour enters through the historical entrance and takes you by the saltpeter artifacts and walks you through some of the largest trunk passages in Mammoth Cave.
The saltpeter artifacts are from the time period around the War of 1812. Mammoth Cave became a valuable commercial property with the outbreak of the War of 1812 between the United States and England. Cave sediments with abundant quantities of nitrate, an essential ingredient of gunpowder, were mined by slaves during the war.
Helpful maps: Park Map & Detail Map.