In 2013, The Mütter Museum in Philadelphia added a few extraordinary pieces to their permanent galleries. Forty-six to be exact; all of them 20 microns thick, stained violet, and preserved in glass slides. Shown above, they are the tissue samples from the brain of Albert Einstein, on display at only two exhibitions in the world.

When the 76-year-old physicist died in 1955, New Jersey's Princeton Hospital Pathologist Thomas Harvey removed, photographed and preserved Einstein's brain (and eyes) against the knowledge or wishes of Einstein's family, claiming he had prior permission. Harvey would lose his job at Princeton, and over the next 40 years the pathologist would keep the majority of the brain (in cube form) in his possession, sending portions to scientists worldwide to be analyzed and documented.

Dr. Harvey eventually donated a large remainder of the brain back to the pathology department at Princeton Hospital, and in 2010 Harvey's heirs transferred any remaining ownership of Einstein's brain to the National Museum of Health and Medicine.