Hitobashira

Hitobashira (人柱, pilar human). is a kind of human sacrifice formerly practised in ancient Japan, people believed that seal (bury) a human being under a building or close to her, would cause her to be more strong and stable and it wasn't destroyed by floods or enemy attacks ...
By putting people in the pillars and walls, would be made sacrifices to the gods, if they were satisfied, would allow the site to last longer. It is said that the buildings with human pillars are haunted by that are sealed in its beams.

Started with the human sacrifices during construction of the Kofun (aristocratic tombs), and have become tradition in various parts of Japan. Currently practicing hitobashira in construction, however, also called hitobashira workers buried alive working in subhuman conditions.)