If you were one of those kids who read each issue of ZooBooks three or four times each, you’re probably familiar with the concept of echolocation, the ability for bats, dolphins, and whales to “see” through pulses of sound waves. What may surprise you is that a surprising number of humans have essentially trained themselves to do the same thing after losing their eyesight to disease or accident. Daniel Kish, an advocate of rights for and public awareness of the blind, lost his eyes to retinal cancer when he was barely a year old, but soon learned to compensate by making dolphin-like clicking sounds with his tongue. He and his organization have taught human echolocation techniques to over 500 blind children and shown them that they can be as capable of independent movement (including hiking and bicycling) as anyone else. MRI studies of human echolocation users have shown that their brains’ visual cortexes are actually repurposed to process sound in terms of echo, distance, and direction, allowing for a form of sight that allows them to navigate almost any environment and giving them a surprisingly deft sense of distance.