One of the tours I did at while in Pak Chong with the Greanleaf (where I stayed) was a trip to a Bat Cave, which the monks apparently use when meditating., so it was actually called the 'Bat Temple'. It was quite interesting being in a bat cave, but I think what made it even more interesting is the tour guide. He was really good and instead of just regurgitating information like most tour guides do, he found fun ways of sharing and explaining the information, not to mention he would always go out of his way and bring back some sort of interesting creature to us. His passion and excitement just rubs off onto you.
After leaving this bat temple, we drove to a spot where you could see the the main entrance of the bat cave, and at sun set they all leave the cave to go hunting for food. So we watched as thousands and thousands of bats flew out of the cave and what a site it was. When leaving the cave they form like a river, and it was absolutely amazing to see this endless river of bats in the sky, definitely an experience not easily forgotten.