Welcome to Machu Picchu, the legendary lost city of the Inca. You are currently standing at the start of Circuit One, often called the Panoramic Circuit because it offers the most breathtaking, bird’s-eye views of the entire citadel. Situated two thousand four hundred and thirty meters above sea level in the heart of the Peruvian Andes, this site was built in the mid-fifteenth century under the orders of the great Inca ruler, Pachacuti.[3] As you walk along these ancient paths, notice the dramatic landscape surrounding you.[5] [6] [7] To your right, the Urubamba River snakes through the valley floor, while ahead, the urban and religious sectors of the city emerge from the mist. You are about to walk through a sanctuary that was unknown to the outside world for over four hundred years until its scientific rediscovery in nineteen eleven.