When the traveler on his first visit to Cusco raises his eyes and looks up at the clean and fluffy sky his doubts disappear: To days great adventure is to follow in the footsteps of the ancient dwellers of the Inca Empire. . Why invest up to four days trekking on steep paths to reach the old citadel of Machu Picchu, if there is a railroad that can take you there in comfort in only six hours? Only the experience itself can supply the answer.