While researching bats for one of her films, documentary filmmaker Carol Foster learned that humans were also doing what bats could do, namely using echolocation to see.That set her off on a project to help the blind in Belize learn this amazing skill. She’s even launched a crowdfunding campaign on Indiegogo to fund the effort. In this interview, we talk about what we can learn from bats and how the blind uses flash sonar to see the world.