Welcome to Cat Street, a winding, pedestrian-friendly lane that meanders between the districts of Harajuku and Shibuya in Tokyo. It is roughly a kilometer long, which makes it short enough for an easy afternoon stroll but dense enough to fill the whole afternoon. This guide tells the story of the street itself and its surrounding neighborhoods. Here is the first surprise. Despite the name, you will not find cats on the street. Its official name is far less catchy: Kyu-Shibuya-gawa Yuhodoro, which means Old Shibuya River Pedestrian Lane. That name holds the key to the whole place, because the path you walk on was once a river. Over the next few stops we will follow that river underground, look at how a quiet back route became known as the spiritual home of Tokyo street fashion, and talk about the street's puzzling nickname. Take your time. Cat Street rewards slow walking and a habit of looking up, down and sideways.