Nan Ungol

Nan Ungol is seen in Maps of Middle-earth for Decipher's The Lord of the Rings Roleplaying Game as a small valley in the bottom left corner of Mordor, without any further exposition. A revision of this map is used as merchandise for The Lord of the Rings: The Return of the King. In Middle-earth: Shadow of Mordor, it is mentioned that while some of Shelob's children, traveling south, have

taken Nan Ungol (Sindarin for "Valley of the Spiders") as their primary home, they've since spread across Mordor taking residence in its caves and other dark places, and are actively reporting back to their queen.

There, it is said that "Their nests and lairs are littered with the crushed bones of their prey" and none who enter this valley come back alive.