In southern Peru stands an Inca city, uninhabited for several centuries but still virtually intact: Machu Picchu. Discovered in the early 20th century, it attracts a million visitors every year from the four corners of the globe to admire the skills of the powerful civilization that built it. At an altitude of more than 2,400 metres, the Incas managed to carve out a deep ridge to erect a masterpiece of... see more