A blocked cellar drop. This had been the only ventilation to the cellar. Without good ventialtion cellars become damp. Still air also encourages dry rot.

Dry rot infested door frame. The problem with dry rot is that it can travel from a source of moisture to other parts of the building which are dry.

Fungus on a wall. Porbably a wet rot.

Beetles also like damp timber. Dust form their boring has been trappd by the cobwebs

Open flued boiler in an unventilted cellar. Extreme danger of carbon monoxide poisioning