(An-Naml) 27 : 58
وَأَمْطَرْنَا عَلَيْهِمْ مَطَرًا ۖ فَسَاءَ مَطَرُ الْمُنْذَرِينَ
And We rained upon them a rain, then what an evil rain was showered upon those who were warned.
Rain of baked stones was showered upon the transgressed and wrongdoing people of Looth as the punishment. And the Dead Sea was formed as the consequence of their punishment to make it as the Sign of those who do such shameful and heinous deeds. See explanation 15: 76 and 26: 160-173.