The Heap is the stench zone in Hobopolis. During combat, stench damage is taken over time.
A primary stat of 350 is suggested. If your main stat isn't high enough, you'll see the following message:
The buzzing of flies assaults your ears as you near the Heap, but the ear trauma is nothing compared to the flat-out war the Heap is waging on your nasal cavities. You're not sure you can fight here and keep your lunch down.
(It is recommended that you have at least 350 <mainstat> to adventure here.)
Explore the junkpile: Drops three items, which seem to be randomly chosen from a subset of all the items in-game. Seems to reset the stench level to the minimum.