The Nativity by Botticelli

Do you blame me that I sit for hours before this picture?
But if I walked all over the world in time
I should hardly see anything worth seeing that is not in this picture.

~G.K. Chesterton: Notebooks, mid 1890's.

The Mystical Nativity, by Sandro Botticelli. 
Tempera on canvas, c. 1500; National Gallery, London.
(click on image to enlarge)