These days, a subway is an integral part of a city's heritage and a key feature of the urban landscape used by passengers, but subways are also full of history and art. They reflect a city's personality and its past and future, and are worthy of exploration, even for those not boarding a train. It's safe to say that a great many subways have overcome their past reputation for unpleasant shadiness.

Subways revolutionized urban transport, moving people from crowded streets to efficient underground tunnels. This book has two parts: the first tells the stories of six major subways:...