When reading "Alice's Adventures in Wonderland," most readers visualize the queen’s croquet game play out in their heads. A few might see the scene in vivid detail. However, a small fraction of readers have a drastically different experience: within their heads, they "see" absolutely nothing. Why do some people have an inability to visualize images? Adam Zeman explores the science of aphantasia. Lesson by Adam Zeman, directed by Biljana Labović. Animation by Manon David.