[UDUN]Fortress of Angband

The name Udûn is much less common as a name for Melkor's fortress than the equivalent Utumno. In The Lord of the Rings it appears just once, in Gandalf's quote given above. It survived, though, as a name for the northern valley of Mordor that lay behind the Morannon. No doubt Sauron chose this name in memory of his ancient master's greatest stronghold.