West Tower corridor

"They slipped through the doorway behind them and down a tightly spiralling stone staircase. As they reached the bottom of it, they heard voices. They flattened themselves against the wall and listened. It sounded like Fudge and Snape. They were walking quickly along the corridor at the foot of the staircase."

- Narrative

The West Tower battlements can be accessed by a corridor leading to a tightly spiralling stone staircase. Another staircase leads down towards a third staircase which allows access to the hospital wing corridor. Severus Snape and Cornelius Fudge discussed Sirius Black while walking along the corridor, likely on their way to Filius Flitwick's office.

Appearances

 * Harry Potter and the Prisoner of Azkaban