What are the regions where Allah sent down punishment, and what is the obligation towards them, with evidence?

Among the places where punishment descended are: Al-Ahqaf (the land of 'Ad), Al-Hijr (the land of Thamud), the land of the people of Lut, the land of Madyan (the people of Shu'ayb), the land of Al-Jannah near Sana'a, and the graves of the wrongdoers and disbelievers.

Regarding these places, it is obligatory: not to enter them except with weeping and awe, to take heed and reflect on what befell their inhabitants and to beware of following their path, not to drink from their wells or knead dough with their water, and to hasten through them while covering one's head if one is compelled to pass through.