At https://phys.org/print423401228.html … William sent in this one. A Roman city off the NE coast of Tunisia with streets, monuments, and tanks used to produce garum (a fermented fish based condiment) has been found by archaeologists – submerged. The suggestion is that it was overwhelmed by a tsunami – which begs the question, then why did it remain submerged? Earthquakes in the Mediterranean are common and many classical Greek and Roman towns and cities on the coast were subject to tectonic subsidence – a more likely explanation than a tsunami wave. The site was known as Neapolis and was a recognised manufacturing base for garum – and salted fish. More to come as this seems to be a provisional news story and exploration continues.