Unexplored passage to Hogsmeade

This unexplored passage to Hogsmeade was one of the seven passages known to the Marauders that led to Hogsmeade from Hogwarts Castle. It was located off of the Hieroglyphic Hall. Judging by how it was labeled on the Marauder's Map, the Marauders never explored this passage for whatever reason. Aside from the Marauders and other owners of their Map like the Weasley twins and Harry Potter, Argus Filch knew of the existence of this passage.

Appearances

 * Harry Potter and the Prisoner of Azkaban
 * The Making of Harry Potter