Despite all of today's fleeting architectural directions, there is one that persists - the decades-long trend for structures resembling mounds or caves and appearing to emerge from the earth itself. And it's no longer only stubborn eco-fanatics and Earthship enthusiasts who dream of living underground. Thanks to Peter Jackson's Lord of the Rings and The Hobbit trilogies, the earth house concept has enjoyed a resurgence, earning fans from all walks of life. What unites all of the builders and architects is their desire to create structures that exist in harmony with the natural environment. Existing caves or hollows are often used and natural materials such as earth, clay and straw - but sometimes modern materials too such as concrete - are integrated. Through numerous examples, this volume presents the broad diversity of this architectural trend, explains the sustainable qualities of the projects and illustrates the interiors of these highly individual structures.