High in the Andes mountains of Peru, around the year 1481, Incan stonemasons were busy carving a city from the clouds. Their emperor, Pachacuti, had ordered a royal estate built on a knife-edge ridge between two towering peaks. They called it Machu Picchu, meaning Old Mountain. To get there, you had to climb thousands of feet along narrow paths, and once you arrived, you stood almost 8,000 feet above sea level with mist drifting through the temples.
The builders had no metal tools, no wheels, and no written plans, yet they fit giant stones together so precisely that you still can't slip a knife blade between them. They carved terraces into the mountainside for growing potatoes and corn, built fountains fed by mountain springs, and aligned temples with the sun's path so that on special days, light would strike just the right stone. About 750 people lived there at its peak, including priests, servants, and llama herders.
Then, less than a hundred years later, the Inca abandoned Machu Picchu. Nobody is completely sure why - maybe the Spanish conquest in 1532, maybe disease. Vines and jungle swallowed the city. Locals knew it was there, but the wider world forgot. In 1911, American explorer Hiram Bingham, led by a young Quechua boy, climbed up the mountain and rediscovered the ruins. Today Machu Picchu is one of the most visited places on Earth, and engineers still study its earthquake-proof stonework, hoping to crack the secrets of the Inca masters.
