Human body

Humans are born with about 300 bones, but many fuse together during growth, leaving adults with approximately 206.

74% of Korean adults have only two bones in their little toe, compared to just 35.5% in Europe.

Submerging your face in cold water triggers the "diving reflex." Heart rate drops 10-25% and blood flow shifts to protect the brain and heart. This ancient mammalian reflex is especially strong in babies under six months.

Close one eye, extend your thumb to align with a distant object, then switch eyes. The object appears to shift. Multiply that apparent shift by 10 to get the actual distance. This works because the ratio between your eyes and your arm length is roughly 1:10.