In southern Peru lies one of mankind's greatest mysteries - 1000's of giant shapes etched into the desert sands. We reveal who made them and why. Etched, as if by giants, onto the arid moonscape of Peru's southern desert lies one of man's greatest mysteries; the Nasca Lines. More than 15,000 geometric and animal-like patterns have been discovered criss-crossing the pampas like a vast puzzle. Who built them and what was their purpose? Ancient racetracks, landing strips for aliens, or perhaps a giant astronomical calendar? And are the Lines connected to the gruesome discovery of large cache's of severed human heads. Now, after decades of misunderstanding, modern archaeology may finally have the answer. Excavations in the surrounding mountains are uncovering extraordinary clues about the people who made them and why. A long since vanished people, called the Nasca, flourished here between 200BC and 700AD. But the harsh environment led them to extreme measures in order to survive. Archaeolo