What is the human body’s largest organ?

The answer is: Skin

Your skin has always been the undisputed champion of organ size. The ancient Greeks figured this out pretty early, seeing it as way more than nature's grocery bag. To them it was a complex organ absolutely essential to keeping us alive.

Through the centuries, scientists (including one particularly dedicated French guy who did his research by candlelight) have discovered just how amazing skin really is. Besides famously creating its own vitamin D, it also keeps out germs and helps regulate our temperature. It's packed with nerve endings that catch every breeze and blood vessels that help control your temperature.

Your skin covers about 22 square feet, roughly the size of a twin bed, and makes up about 15% of your body weight. Compare that to your brain at just 2%. Every single square inch contains millions of cells, thousands of nerve endings, and enough blood vessels to stretch 20 feet.

The more we study skin, the cooler it gets. Scientists recently discovered it has its own ecosystem of helpful bacteria, makes its own antimicrobial compounds, and can even smell things. The ancient Greeks were right all along. This massive organ isn't just hanging around, it's running the show.