Who, how, and why was Stonehenge built? The famous megalithic circle on Salisbury Plain in southwest England is the focus of the new novel by Ken Follett (Cardiff, 1949). Although the author is preparing for a promotional tour that will take him starting next week through the United States, France, Germany, Italy and Spain, having already passed through Denmark, this Monday he revealed in the British capital some of the keys and motivations for writing The Circle of Days (Rosa dels Vents, translated into Catalan by Mireia Alegre Clanxet and Imma Estany Morros), which arrives in Catalan bookstores on September 23.