Photographed by Alfonso Rodríguez-Baeza and Marisa Ortega-Sánchez, 2009.  A scanning electron microscope (SEM) image zooms in on the baroque branching structures that send blood to the human brain’s cortex.  The vessels are organised such that the large blood vessels (top of image) surround the surface of the brain, sending thin, dense projections down into the depths of the cortex (bottom of image).
photo source: LiveScience from InsideTheBrainAJourneyThroughTime