We tend to send things underground that we are not interested in ever seeing again. Sewage. Garbage. In the past, we have used the underground to age such provisions as cheese and beer. In , geologist, historian, and urban speleologist Greg Brick takes us on an adventurous, educational, and—thankfully— tour beneath the streets and into the myriad tunnels, caves, and industrial spaces that make up the Twin Cities’ fascinating and surprisingly vast underground landscape.