Forests of Balor
The Forests of Balor is a vast wooded area in Albion; it is likely that the forests grow in a country called Balor. The forests are home to creatures such as giant spiders (Balorian Spiders), which live in the caves deep beneath the forest, and the cockatrice, a dangerous lizard like animal. Flora growing in the forests include the Mortaeus tree, on the roots of which the Mortaeus flower grows. This is where Arthur and Nimueh met when Arthur went on a quest to retrive the Mortaeues flower in order to save Merlin from a deadly poison, (The Poisoned Chalice). It is highly likely that Nimueh's caves were located in that area, as she seemed to know the cave system in that area well enough to guide and trap Arthur at a dead end.
The Caves of Balor.