The Nazca Lines are one of mankind’s great unsolved mysteries. More than 15,000 “geoglyphs” are etched into the desert sands of southern Peru. But who built them and what was their purpose? Today, scientists are looking for clues. Can a three-dimensional digital map of the Lines help determine their true meaning? And are the Lines connected to the gruesome discovery of large caches of severed human heads? Now, after decades of misunderstanding, modern archaeology may finally have the answer.