Comment by nlawalker

A favorite "today I learned" of mine is that staircases in medieval castles were constructed with steps of slightly different heights in order to trip invaders. In particular, the last step at the top of a staircase was tall, with the intent of causing a stumble and generating a loud footfall (for those sneaking around) or sending the intruder into the room headfirst (into a ready weapon, in the case of a siege).