Today's challenge was to photograph something on the theme "Down".
Spiral staircases, in all their forms, often make attractive photographs; it is something about the symmetry, the regularity of the repeating pattern, the sense of depth in the image.
This shot is looking down on a narrow spiral staircase which winds tightly around the central colum.
OK, for the scientists among you, I accept that - strictly - this is not a spiral staircase but a helical staircase. But now is not the time for pedantry.