A Mordor fortress with the Spire - the glow effect is the prerequisite upgrade, Morgul Sorcery
The Gorgoroth Spire is the final Mordor fortress upgrade, requiring Morgul Sorcery. It is a tower, at the apex of which is a statue of the Great Eye - and it allows the use of a great fireball to cause massive fire-destruction on a selected area.
Cost: 2500