Travel Murder shafts.

Our driver was telling us about the murder shafts.  Most castle were equipped with very strong outer doors that lead to a room about five foot five that was open up top, it had a other very strong door that would enter the castle.  The purpose was if the enemy managed to batter down the first door you could attack from up top while they tried to batter down the last door.  they would use arrows boiling oil or whatever they could find.  Boiling oil imagine that. What an awful and cruel way to fight a war.  But as they say all is fair in love and war.