It might have been alien visitors, but I have no final opinion about that. I don't know who it was. No idea, in fact. It might have simply been an earlier civilization of humans who had advanced technology which was later lost, due to war or natural disasters of some kind.

However, I think it far more likely that weapons similar to our present nuclear bombs were used to suddenly destroy those two cities...than Angels or an enraged deity hurling thunderbolts! :-)

The latter version is what I call bollox.

There are higher than average levels of radiation still present in the geographical area where those cities stood, and there is physical evidence present in the form of "green glass", melted out of the sand on the surface there by the intense heat of the nuclear fire.

The third alternative is that nothing happened there at all...in which case the ancient people made up a very significant legend about the sudden destruction of 2 cities on the basis of something that never happened. And that is about as likely as the Angels and thunderbolts story....

Legends are a simple people's way to try to describe something that happened long before their birth in terms that they can understand in their own context.

Pied Piper has no other rational argument to put forward about Sodom and Gomorrah, he just automatically denies anything he doesn't already believe, and ridicules it. This has been the reaction of the conventional mind ever since our ancestors crawled out of the trees or the cave or the neighborhood pub or wherever.... The conventional mind is proud of its very narrow horizons and defends them in a predictable fashion. It already figures that it knows all it needs to know in order to earn a living, get laid, etc...

Well, yes, but that's all an animal knows too.