Over the bridge, and south of Appie's shop, you can find
the entrance to Piet Sewers. If you're on your way out of Piet, you can reach Pravat Cave, or Mehadi Swamp.

Piet Sewers (minimum insight - 11)

Common Monsters:
Frog, Crab, Anemone, Turtle

Common Spoils:
Frog's Leg, Crab's Claw, Turtle's Shell, and other useless items.

Other Features:
There is a quest involving unclogging the Piet sewers. More information can be learned from Jay, court jester in Loures.