thats not atlantis, though it may have been built by atlanteans. there is a large land mass in the atlantic and assuming the biblical floods were correct (also the native cubans have a myth that there was a city which disappeared overnight into the ocean (your link)) tectonic plates very well could have shifted and lowered the land mass underwater. sea levels were also 400 feet lower ~11,000 years ago. what caused the shifting? meteor impact, divine intervention, you tell me.