The Dark Tower is a menacing place that haunts the Dreams of men and instills fear to those who even think about it. It is accessible through a forest known as the Impenetrable Forest, but relies on going the opposite way to which you think, hence why the sun has a shadow pointing east whilst it is rising. The plains that lie before the Tower have hundreds of dead men, which sharp swords and spears pointing out of the ground.
The Interior of the tower is full of winding corridors and rooms, some of which contain deadly traps or horrific visions.
It was said by Queen Mab that the tower only exists in one's mind.
When Queen Guinevere was passing through the forest on the way back to seeing her fathers memorial, she and a group of knights were ambushed by Morgana who used snakes to frighten the horses and bite Percival and Leon. Gwen managed to escape, but Morgana herself lay in her path. She tried to get away but Morgana used her magic to throw Gwen off. Morgana then took Gwen to this tower and placed her in a room full of Mandrake Roots which made Gwen see her brother and other knights laughing at her, appearing in cold visions. Word got to Camelot and Arthur went out to find his Queen. Whilst on their way, Percival and Leon had dreams of the Tower, probably invoked by Morgana's snakes. They eventually find the tower, whilst travelling through a dense forest in which a fairy like figure known as Mab warns Emrys that one will not return. They manage to get there through walking the opposite way to which they should and go across the plains. Inside the tower, they pass a trap where they must tread carefully or else a dart would be fired. By the time of this, Gwen was mentally distraught and seemingly gave in to Morgana. Sir Elyan broke into the room which Gwen was inside. Surrounding her was an animate sword which Elyan was fatally wounded by. The Knights discovered Gwen and they escaped the tower, not knowing what really went on inside with Morgana.