They are similar to the marble caves in that you need a boat and a guide, who knows what he is doing, to fully explore them. What is different are the glowworms themselves. These creatures are larvae with their very own bioluminescence(the glow, obviously), resembling worms. And there are a lot of them! The cave formation is quite young and still at the mercy of the underground rivers. It is very dark down there but this only makes the adventure better.
