Yeah, there's the "abandoned" underwater cities, officially.

I do agree that it's ridiculous if people think we are alone in the universe etc... (Allow me the suggestion, there is a great book "Passport to the Cosmos" on that topic)

But I believe people should be careful with this alien topic. Things like, how it's being used to push the one religion and project Bluebeam, should be mentioned/ researched from time to time.

Not that you asked my opinion hehehe but here it is.