The Aztecs have fascinated and horrified Westerners for centuries. After Cortes' extraordinary conquest of the New World's most powerful civilization in 1521, the Aztec capital, Tenochtitlan, was levelled and its Great Temple demolished. Soon even the location of the old cult centre was lost - until 1978, when tunnelling for Mexico City's subway system unearthed clues that led to the rediscovery of the Great Temple and the most spectacular series of excavations ever conducted in Mexico.