If they know where they are they are not lost................
Always in the last place ya look, unless ya got the identification wrong of course. :^)
I like how GR kept a tight focus and only covered seven, but offhand mentioned for example the city that slid down Mount Sipylus and into the lake that's still there, per one ancient source. Eberhard Zangger posits that the destruction of the currently unverified city is the "real" Atlantis.
Another way to look at this is that cities serve a purpose, if that purpose no longer exist they cease to exist.
The insane climate change warriors act as if a city is some how important because it is a city and not because of the function. Let us say that the climate warriors are correct and New York sinks into the the ocean. Would New York be rebuilt or abandoned? Personally I think New York has lost it’s reason to exist and if destroyed would not be rebuilt as it was (but if rebuilt it would be for another purpose).
Climate change is real but instead of destroying your culture, economy, and nation why not simply plan on how to adapt to any climate change? Before air conditioning there were many places in the US uncomfortable to live and work, that is technology that helps us adapt to hot climates.