Going to brazil...

[Melbies]

Hey I'm going on a trip to Brazil (Rio De Janiero & Salvador) in October with my parents and a friend and were looking to make this trip the best possible. Caving is something on the top of our list but we know nothing about it. All the tours/activities we find online are multiple-day trips and were only looking for a single day thing. Anyone recommend a good site for that? Like I said, we know nothing. Where are the best caves? How much does it cost? How safe is it? Any help at all would be greatly appreciated.