Daniel Kish was born with an aggressive form of cancer called retinoblastoma, which attacks the retinas. To save his life, both of his eyes were removed by the time he was 13 months old. Since his infancy — Kish is now 44 — he has been adapting to his blindness in such remarkable ways that some people have wondered if he’s playing a grand practical joke. But Kish, I can confirm, is completely blind. He knew my car was poorly parked because he produced a brief, sharp click with his tongue. The sound waves he created traveled at a speed of more than 1,000 feet per second, bounced off every object around him, and returned to his ears at the same rate, though vastly decreased in volume.