The first thing that strikes you when you come into the cathedral is its great height. You look up and up and up! This wonderful painted ceiling runs the length of the nave and was painted (so the children's guide to the cathedral told me) by two different painters. (Shown apparently by a stronger use of colour towards the end).
This is only the two upper levels of the north aisle (transept?).
You can see the full height here in the centre of the cathedral under the octagon, which is topped by its lantern tower made of wood, lead and glass.
Many of the walls, pillars and arches within the cathedral are heavily decorated and you can still see traces of painted decoration in many places.