5 fun facts about hearing:

Fish do not have ears, but they can hear pressure changes through ridges on their body.
The ear’s malleus, incus and stapes (otherwise known as the hammer, anvil and stirrup) are the smallest bones in the human body. All three together could fit together on a penny.
The ear continues to hear sounds, even while you sleep.
Sound travels at the speed of 1,130 feet per second, or 770 miles per hour.
Sitting in front of the speakers at a rock concert can expose you to 120 decibels, which will begin to damage hearing in only 7 1/2 minutes.