There are ancient ROMAN era docks that are under water, so 2000 year per meter or so................
Earthquakes have caused some areas to sink below water, then rise again centuries later.
One temple on the shore in Italy has markings of barnacles on it showing it has been under the sea at some time in the ancient past.
Cleopatra’s palace is underwater in Alexandria, caused by the Big Quakes in the eastern Med back in 115 AD and 365 AD.