When it rains, the topsoil lets H20 ( water ) flow through it, so it can go to plant roots. But, when C02 ( carbon dioxide ) and H20 mix underground, it forms acid ( carbonic ).
The acid erodes away the rock underground with a chemical reaction, which forms this cave!
Overtime it gets bigger and forms stalactites as well! They might be different sizes, but it depends on how old they are!
Bats are the most known animal in caves. They like the darkness and they sleep in the day, and roam at night. They use echolocation to get around the cave, because they have bad eyesight. Yet some people say their sight is just as good as humans! That's cool to think about!
People have found very interesting items or sights, like ancient items in a cave! People can conclude that some people back then lived in these caves!
Whenever you have the time, I suggest going to a cave! You won't regret it.