This major tourist attraction is housed under some of the existing arches of the London and Greenwich Railway line. There is very little actually written history of the building as it is today but it is has previously been used as a stable block, wine cellar and possibly an orphanage. From 1212 The Hospital of St. Thomas The Martyr stood on the site of the dungeon. It was run by a mixed order of nuns and monks and provided shelter and treatment for the poor, sick and homeless. During WWII the railway arches were used as air raid shelters but were themselves bombed in February 1941. It is believed that the bodies of many of the victims were never recovered and that they remain entombed in the arches to this day. Shadowy figures have been seen throughout the dungeon, while a male figure dressed all in black is thought to have an evil, negative presence. A member of staff has apparently seen a group of children playing ring-a-ring-o-roses, while in the 'Pre-Plague' area a man and two children are regularly seen who mysteriously disappear upon approach. The naked top half of a man has been seen apparently floating in the 'London Bridge' area, while a phantom man has been seen standing between the waxworks of two men operating on a body in the 'Mortuary' area.

The investigation began with Derek's walk, where he apparently connected with the notorious Jack The Ripper who apparently comes in visitation as a result of the dungeon's homage to his deeds. Derek suggested that he also would have murdered one of his victims nearby, however all known evidence suggests that this in untrue. He also connected with a 'Copycat Killer', believed to be James Maybrick, however Ciaran's analysis provided evidence to suggest that this was merely a false rumour started by an author of a related book, hence his presence in the dungeon was also a confusion. Derek finally suggested a connection with Oliver Cromwell, however again Ciaran was unable to verify any such association. During the walk around Yvette appeared to identify a number of anomalous audibles, some of which appeared to sound like human sounds but which were not clear enough to verify. David Wells alternatively appeared to make less distinguished connections, linking in with a frustrated and angry man with his family and who in their day had been poor, and resented people of any discernable wealth. A number of light anomalies were also picked up on camera during David's walk around. The team were then joined for the vigils by Fred Batt, owner of the Clockhouse and Caesars Nightclub (featured in Series 2). A number of strange noises, as if objects were being thrown around, were picked up during a vigil conducted by Stuart, Karl and Jon in one of the deserted and derelict areas of the dungeon. This section was coincidentally strewn with rubble and masonry, hence this could have accounted for many of he noises. At one point however a single strip of wood did appear to land within the middle of the group. Meanwhile during a séance involving Fred, David and Yvette, the crew attempted to contact a group of mischievous children who appeared to be making noises, while Fred also suggested that he had felt his leg being kicked from behind.