Twisty streets that would be alleys anywhere else, clearly designed (probably the wrong word, the streets look more like evolution than intelligent design) for something other than cars. Buildings of old brick tower on each side- you can't tell if the sun shines without going outside and looking up. Fire escapes don't go to the ground but to the next building. In case of fire, kick in your neighbor's window.
On the weekends, the place is thick with tourists-- wandering for the most part...