If I were writing a science fiction story there would be primitive villages on higher inland areas, and partially submerged technologically advanced cities on the coastlines :-)

But what I find most amusing is that when I was a kid "science" was saying "but we don't know if any other star even has a planet!" and to me as a kid it seemed preposterous that other stars wouldn't have planets. And now of course we know that pretty much ever star has at least some planets. The unusual case is no planets.

Similarly with life, it seems ridiculous to think that somehow this planet at this time was the only place anywhere that sentience emerged. So it really makes me wonder, why the heck aren't we already talking with them?

What is it that keeps intelligent life that originated on other planets from communicating with the intelligent life living on this planet? Why won't they talk to us?