Following supper, we meandered through the curvy streets of the (mostly closed) shopping district. There was an outdoor Christmas market - one of the few times we've seen a shopping area open late.
Clifford's Tower (above) is the remains of York Castle, originally built by William the Conqueror. This was the site of a violent incident in 1190, when the Jewish community was assailed by a mob. Taking refuge in the castle, the Jews committed suicide and set fire to the castle, rather than fall to the mob. In 1290, Jews were expelled from England by royal edict, which was not overturned until 1656.
I learned that spiral staircases were built to rise in a clockwise manner. This gives (right-handed) defenders the advantage: as one backs up the stairs, his right hand is free for swordplay. You lefties will just have to design your own castles, or make sure you are the aggressors, going up the stairs.