1. Goosebumps evolved to make our ancestors’ hair stand up, making them appear more threatening to predators.


3. If they were laid end to end, all of the blood vessels in the human body would encircle the Earth four times.

Flowers for Sale

 5.  The human nose can detect about 1 trillion smells.


7. Belly buttons grow special hairs to catch lint. 


9.   Your tongue is made up of eight interwoven muscles, similar in structure to an elephant’s trunk or an octopus’s tentacle.

Sleepy Baby

2. Scientists aren't exactly sure why we yawn, but it may help regulate body temperature.

Beautiful Smile

4. Humans are the only animals with chins.


6. As you breathe, most of the air is going in and out of one nostril. Every few hours, the workload shifts to the other nostril.

Hair Cut

8. Hair grows fast—about 6 inches per year. The only thing in the body that grows faster is bone marrow.


10.  The satisfying sound of cracking your knuckles comes from gas bubbles bursting in your joints.

Red love heart on hearts

11.   The heart beats more than 3 billion times in the average human lifespan.


13.   Extraocular muscles in the eye are the body’s fastest muscles. They allow both of your eyes to flick in the same direction in a single 50-millisecond movement.

Brain Scans

12.  A surgical procedure called a selective amygdalohippocampectomy removes half of the brain’s amygdala—and with it, the patient’s sense of fear.

Happy Twins

14. On a genetic level, all human beings are more than 99 percent identical.