In general, the caves are the most reliable sources that give information about how the earth used to be many years ago. So we find answers to the questions asked about the evolution of the earth (globe). Sea caves give information about the geographical location, water levels, coastal features of the seas in the ancient times.
The diving in the open seas and the cave diving are completely different from each other. Cave diving is the most technical and dangerous one among the diving types. For this reason, it requires a different and particular training.