The entrance to the Obelisk of Water is located here.
The Obelisk of Fire are located here.
Quest info:
This area is part of the Scorpion Catcher Quest. One of the Kharid Scorpions is located here.
This area is part of the Hero's Quest. Lava Eel is caught here.
Notes:
If you loose your Dusty Key, you can get another from Velrak the Explorer. He is in a jail cell the southern part of the area, where the Black Knights (level 33) are. Kill the Jailer (level 47) to get the key to the cell.