Click on the picture!
Top: 2012 Nikon Small World 4 th place winner. Drosophila visual system halfway through pupal development. Retina (gold), photoreceptor axons (blue), and brain (green) (1500x). By Dr. W. Ryan Williamson
Bottom: The same, drawn by Santiago Ramón Y Cajal in
(Source, my neurosience textbook, with my writings :) )