WHY did the so much land become submerged?

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It's the elephant in the room. I can't find anything on the reason why so much land, still containing 3 cities in Hellenistic times, became submerged in such a (geologically speaking) short time. Arminden (talk) 10:53, 2 August 2021 (UTC)Reply

Even in Roman times. A geology paragraph is urgently needed. Arminden (talk) 10:56, 2 August 2021 (UTC)Reply

I have opened a discussion here: Talk:Egypt#Submersion of coastal land. Arminden (talk) 12:43, 2 August 2021 (UTC)Reply