Clockwise staircases

Spiral staircases in medieval castles are running clockwise. This is because all knights used to be
right-handed. When the intruding army would climb the stairs they would not be able to use their right hand which was holding the sword because of the difficulties of climbing the stairs. Left-handed knights would have had no troubles, except left-handed people could never become knights because it was assumed that they were descendants of the devil.