There are around 60,000 miles of blood vessels in the human body. If you took them all out and laid them end to end, they’d stretch around the world more than twice.
A blue whale's tongue weighs as much as an elephant.
The smallest bone in your body is in your ear.
If you take all the letters from the word "wizard" and swap them with opposite letters (a->z, b->y), it spells wizard backwards.