Chris,
This is marvellous! First of all you've chosen a good viewpoint here which shows the scale of the gallery and the multiple layers, also the angles of the staircases are very attractive and you've made good use of the extensive DOF of the A200. What really stands out in this shot is that the people add to it - each of the visitors (especially at top left) is in the middle of doing something (for instance the boy dangling his arms). Plenty of human interest helps!
Mike.