Memorizing 25,000 city streets balloons the hippocampus.
Streets in Manhattan are arranged in a user-friendly grid. Twenty dministrative districts, or arrondissements, form a clockwise spiral around the Seine in Paris. London is a different story. A map of its streets looks more like a tangle of yarn that a preschooler glued to construction paper than a metropolis designed with architectural foresight. Yet London’s taxi drivers navigate the smoggy snarl with ease, instantaneously calculating the swiftest route between any two points.