Five hundred years before the Inca, a remarkable band of warriors called the Chachapoya built the greatest stone monument in the Americas. Amazingly, it's three times the size of Egypt's largest pyramid! Yet their civilization vanished almost without a trace.

Hunter Ellis accompanies a team of archaeologists to this majestic site in remote northern Peru. Serious explorations have only been underway since 1997, and there's no telling what secrets will be revealed on this expedition!