Our brain is puzzling. It is curiously large given the size of our bodies, and uses a tremendous amount of energy for its weight. No other animal’s brain compares. Neuroscientist Suzana Herculano-Houzel put on her detective cap to lead us through these mysteries, starting with a big question: Exactly how many cells are in our brains? (No one had ever counted — until she did.) Watch now ยปEffort