A mile-high skyscraper, a dome covering most of downtown Manhattan, a triumphal arch in the form of an elephant - some of the most exciting buildings in the history of architecture are the ones that were never built. A new book, Phantom Architecture, reveals the stories behind more than 50 unbuilt structures, describing how they were conceived, exploring their incredible variety and showing how they went on to inspire other architects who created some of Britain's best known landmarks. Phantom Architecture also shows how London could have looked should some architects have had their way - including a pyramid cemetery...