The greatest mystery of the Americas, the Nasca Lines have intrigued both scientists and the public ever since their existence became known to the Western World only 30 years ago. Straight lines running for miles, others outlining huge birds and mysterious figures are drawn inexplicably on the surface of a baked and arid landscape. Now Chronicle mounts its own investigation into the mystery of 'the largest astronomy book in the world' guided by English explorer Tony Morrison. His journey takes him across inhospitable deserts and high into the freezing isolation of the Andes. The result is a startlingly new theory involving historians, archaeologists, anthropologists and, most importantly of all, the people of the Andes themselves.