the brazilian speleological association - sbe lists the most important caves in rio de janeiro's state as pedra santa (170 m), paulo e virgínia(94 m), gruta da praia do sono (90 m), dos órgãos (80 m), gruta do morcego(75 m), luís fernandes  (63 m), belmiro(59 m), manoel congo (38 m), cassununga (37 m), da imprensa (25 m), while the deepest as gruta dos sete salões (30 m), gruta do morcego(23 m), da imprensa (15 m), manoel congo (10,5 m), luís fernandes (10 m), órgãos (10 m), paulo e virgínia(10 m), pedra santa (10 m), novo tempo (9 m), and da praia do sono (7 m).   

while caves are fascinating environments, they still remain some of the most dangerous spaces where to venture, in rio de janeiro like anywhere else - narrow passages, wet and slippery slopes, darkness, lose rocks, protruding ceilings are just some of the obstacles faced while caving.