The brain is an organ that is orders of magnitude more complex than any other organ in the body. The brain has 100 billion cells. Each of the areas of the brain is organized cytoarchitecturally differently, and the cells connect via over 30 trillion synapses. Compare this to the heart, the liver, the gastrointestinal system, or the lungs, and there is no comparison in terms of complexity and intricacy.
This paragraph is taken from a Medscape article by Dr. Jeffrey A. Lieberman, MD. The article is not relevant, but I found this particular passage fascinating, and wanted to share it.