Our kids have always wanted to visit a cave since their Octonauts lovin' days. What better cave to visit than Mammoth Cave, the longest cave system known in the world. There are many different park tours , but we bought the Historic Tour ($20 for adults, $15 for kids ages 6 to 12, and free for kids 5 and under). We've been stalking tickets for weeks now as we're usually last minute travelers and don't like to purchase tickets in advance, but the Historic Tour tickets on a Saturday always sold out (usually 2 to 3 days in advance) so we did purchase them on Wednesday. After a short introduction and talk on safety from our tour guide, we descended into the cave. What surprised me was how quickly we could feel the change in temperature, it was as if an air conditioning unit was blowing cold air at us. While we didn't immediately need our light jackets, the further into the cave we got, the colder it got eventually to around 54°F (compared to 82°F abo...