In-built traps

Related:
* Traps

Crushing ceilings/walls, guillotines in hallways, arrow/spear shooting holes (with bizarre infinite ammo), disappearing floors, massive rolling boulders in staircases, etc.

Crushing ceilings should be judged carefully. Was it a trap or did the ceiling collapse otherwise?

Generally these are the kind that require the building architect to have been in with the planning rather than someone adding them afterwards like regular traps.

Commonly triggered by pressure plates on the floor or similar.