Best known as the twin cities incinerated by God for sexual perversities.

1908 illustration by the Providence Lithograph Company

But it really wasn't about sodomy, but inhospitality.

Nomadic Jewish people depended on the hospitality of strangers to survive.

Why was the law of hospitality so important in the ancient world and its violation a sin against the divine?  Because in ancient societies, once you traveled beyond the borders of your city or tribal territory you were no longer under the protection of your tribe or people and were a stranger or outsider, subject to the arbitrary power and potential harm of another tribe or people.  One could only be safe if the people understood that their own god put the stranger under his protection, and so honored this as a sacred obligation, the violation of which would incur divine punishment.