Thanks for taking a look at this thread.
So the idea here is that there was an advanced human civilization that was brought to its knees twelve thousand years ago at the end of the last ice age. What remained of the global civilization wanted to make sure that they passed on as much of the knowledge they had inherited to those who came after them and knowing that they would need to make sure everything they made would survive even the worst the planet could throw at them. So they built their buildings out of stone and incorporating as much of their knowledge as possible in the buildings.
While the rest of the humanity slipped into a dark age that sent it back to the stone age there were a few groups that fled the continents and settled one islands around the world. The first human civilization had advanced far quicker up the biotech path giving and so in an attempt to stay unnoticed by those that they considered barbarians on the main land they developed biological re-breathers that would allow them to spend as much time under the water as they walked. Next they developed a half body suit that enclosed their legs to give them more power under the water as they increasingly spend more and more time in.
Their cities were located in cave systems that riddle or are mined out of the island rocks. As time went on and their visited the surface of their islands more and more of the town entrances were covered by vegetation and fallen rocks.
Okay so what I am looking for here is to play out the idea that Atlantis may not have been on city and its true roots are older than many people could have guessed. As well as taking some ideas from other ideas on the history of human kind.
I was thinking that someone could uncover a small cave just under the surface of an island that is covered in ancient ruins or carvings that are similar to others found around the world and when people come to study them they end up being studied by the in habitats of the island.
The other idea I had was that someone gets thrown over bored during a storm or they are diving off the islands coast and get trapped inside a underwater cave when their gear stops working.
Nothing is set in stone here so if anything in this interests you let me know and we can work with it to build up a plot around it hopefully.
If anyone is interested in this please let me know.