Not far away, but partially preserved by the mudflat, lies Rungholt. A city of ~1000-1500 (some sources say 3000) inhabitants that was drowned in the Grote Mandrenke (1362 AD). That's a very big city in that time. In my childhood we were told, while wandering the tidal flat, that we should listen closely if we could hear the church bells under the mud. Only in 2023 the whereabouts of the sunken city were definitely confirmed and mapped. "Rungholt" probably means "wrong/low wood".
https://en.wikipedia.org/wiki/Rungholt