They emit a sound that travels through the air and bounces off objects, revealing their location, size and distance.
It's pretty amazing when you think of it—and even more amazing that there is a human out there that can do the same thing.
Daniel Kish, a Californian that has been completely blind since he was a baby, doesn't let his disability inconvenience him.He still leads an active lifestyle outside, including hiking and mountain-biking (two activities best suited for those with eyesight).
His trick is to click his tongue on the roof of his mouth two to three times a second that send back useful sound waves to let him build a mental picture of his surroundings.
The ability has lead him to be called a “real-life Batman,” though I'm pretty sure the Dark Knight had fancy gadgets for this kind of thing—and he wasn't blind (so he's actually cooler than Batman)
But this amazing power DOES sound like something a superhero should have, and is something to cherish for allowing Kish to lead such an active life.
