Teetering on the brink of a spectacular chasm 1.5km beyond the posada (inn) is this 12th-century fortress built to protect pre-Columbian farmlands below and once home to 500 people. Peering over the canyon's edge will reward with views of abandoned terraces and forbidding mountains all around. There's a great echo too. At around 10am, you can sometimes see condors flying above the fortress.