Rungholt

There's a very clear pattern here across all these different cultures.

There is a striking pattern, and we even have historical ones that blend myth and fact, like the city of Rungholt in Germany, which genuinely was a real wealthy trading city completely destroyed and swallowed by a massive storm surge in 1362.

The pattern is incredibly interesting psychologically.

In almost every single one of these stories, the prosperous land is lost suddenly, usually in a single terrifying night, and it's almost always due to a specific human mistake, a moral failing, or a God's sudden anger.