It is described as a 'long wall of white stone, and beyond that, a high pale tower'. From this, it can be inferred that the fortress is made up of a tall tower encased within a wall. It is later stated that there is a courtyard within the walls with near identical 'low-slung buildings'. There is also an underground chamber located in one of the buildings. It was used to house the peculiars under Miss Peregrine's care and also, all the ymbrynes.
From the front entrance, wights and their cargo cross a half-made bridge through the help of a hollowgast.
Library of Souls Edit
The fortress is first mentioned when Jacob, Emma and Addison successfully reach the foot of the Wights' Bridge.