the wall , go for a walk on it and around it,
the Shambles, and market , one of the last of the medieval housing areas.,
The gates, there are many of these around the wall. York Minster gorgeous beautiful building ,Ummm that round thing where a lot of people died and was built by some old king I think. York Castle Museum.(this is a must) The canals all the old churches . It is a very beautiful walkable city.