Isn't this just beautiful? How amazing was this man? Santiago Ramon y Cajal won the Nobel Prize for Medicine in 1906 for this wonderful work. He was one of the first people in the field of neuroscience to research and explore how the brain functions and explain it's structure. The Guardian recently ran an article all about his work (January 18th 2017)
Below is a drawing Cajal made from observations of the Hippocampus, specifically the Astrocytes within the hippocampus.