How Did the Inca Build Machu Picchu?

More than 500 years ago, high in the Andes Mountains of Peru, an extraordinary story of human ambition, determination and engineering began. Thousands of Inca workers gathered on a rugged mountain ridge, facing a construction challenge that must have seemed almost impossible to overcome. Their incredible goal was to build an entire city nearly 8,000 feet above sea level, high above the deep valleys below. They would work among steep cliffs, powerful winds, heavy rainfall and some of the most difficult mountain terrain in South America. There were no cranes, bulldozers, trucks, power tools or modern roads to make this enormous construction project easier. Nearly every part of the project depended on human strength, skilled hands, careful coordination, patience and thousands of people working together. But the builders possessed something incredibly valuable. Generations of engineering and construction knowledge passed from experienced craftsmen to younger workers. During the 1400s, under the rule of the powerful Inca Emperor Pachacuti, construction began on what would eventually become Machu Picchu. Workers first began transforming the rugged mountain ridge, clearing vegetation, moving earth and preparing the difficult terrain for construction. Slowly, the untouched ridge began changing as terraces, stone foundations, pathways and the earliest structures of Machu Picchu appeared. Before magnificent temples, homes or plazas could be constructed, workers first had to make the steep mountain safe enough to build upon. Their first enormous engineering challenge was reshaping the mountain itself into stable ground, capable of supporting an entire settlement. Teams of labourers carved enormous terraces into the steep slopes, gradually creating long, level platforms across the mountainside. Along the edge of each terrace, workers carefully constructed strong stone retaining walls that prevented the soil from sliding downhill. Behind those walls, workers placed carefully arranged layers of large stones, gravel, sand and fertile soil to create stable terraces. These hidden underground layers allowed the intense mountain rainfall to drain through the terraces instead of dangerously collecting beneath them. Once completed, the terraces provided stable areas where the Inca could grow crops, while also supporting structures higher on the mountain. This remarkable system also reduced erosion and helped protect Machu Picchu from dangerous landslides during periods of intense mountain rainfall. With the mountain stabilised, skilled Inca builders could turn their attention toward one of Machu Picchu's greatest achievements, its stonework. Inca quarrymen worked enormous pieces of granite using simple hammerstones and basic tools made from harder pieces of rock. Using repeated physical effort, workers pounded, shaped, smoothed and polished massive granite blocks until they reached the shape they needed. Remarkably, this extraordinary stonework was accomplished without iron tools, powered cutting equipment or any of the machinery builders use today. Shaping granite required enormous patience because every carefully controlled strike slowly brought the stone closer to its final precise shape. Depending on its size and importance, workers could spend countless hours carefully shaping, testing and refining a single piece of granite. The most carefully finished stones were used for Machu Picchu's important temples and other significant structures throughout the mountain settlement. Many of these important buildings used an extraordinary construction technique now known as ashlar masonry, famous for its remarkable precision. Each granite block was repeatedly carved, inspected and adjusted until its unique shape closely matched the stones surrounding it. Workers could test a stone again and again, carefully refining its edges until it fit tightly against the neighbouring blocks. Some joints became so incredibly precise that mortar was unnecessary, allowing massive stones to rest tightly against one another. Many important stone walls were also constructed with a subtle inward angle, improving their stability across the steep mountain terrain. When earthquakes shook the mountain, these carefully fitted stones could move slightly against one another instead of immediately breaking apart. This ingenious construction helped many Inca walls survive centuries of earthquakes, intense rainfall, powerful winds and changing mountain conditions. But creating a functioning settlement high in the Andes required far more engineering than terraces and beautifully constructed stone walls. Inca engineers designed carefully sloped stone canals that could transport water naturally across the steep and uneven mountain terrain. Fresh water from natural mountain springs travelled through these carefully constructed channels and flowed directly into different areas of Machu Picchu. The water eventually reached a series of stone fountains, providing Machu Picchu's inhabitants with reliable access to fresh mountain water. Workers also constructed extensive stone stairways, allowing inhabitants to travel between different elevations across the incredibly steep settlement. Temples, plazas, homes, ceremonial areas and other important buildings were carefully positioned throughout different sections of the mountain ridge. Beyond the buildings, agricultural terraces covered large sections of the surrounding slopes, creating productive farmland high above the valley. Every completed stone wall represented countless hours of difficult physical labour performed by workers using little more than simple tools. Every terrace required careful planning to control rainfall, support enormous amounts of soil and remain stable on the steep mountainside. Every granite block had to be carefully shaped by skilled human hands using simple tools, patience and generations of experience. After being shaped, many of these incredibly heavy stones still had to be transported across steep and difficult mountain terrain. Teams of workers then carefully manoeuvred each massive stone into its exact position within walls, temples, homes and other structures. And they accomplished all of this while working nearly 8,000 feet above sea level in an incredibly challenging mountain environment. Year after year, their work transformed the rugged mountain ridge into an organised settlement filled with terraces, pathways and stone buildings. Beautiful stone structures eventually rose above the green terraces, creating the dramatic mountain landscape that still makes Machu Picchu recognisable today. Long stairways and narrow stone pathways connected homes, temples, plazas, fountains, agricultural terraces and other areas throughout the settlement. High above the clouds, Machu Picchu became an extraordinary demonstration of Inca engineering, organisation, craftsmanship and human determination. But roughly a century after construction began, enormous changes throughout the Inca Empire would completely transform life in the Andes. Machu Picchu was eventually largely abandoned, leaving its carefully constructed stone buildings, pathways, fountains and terraces increasingly quiet and empty. Beyond the mountains, the once powerful Inca Empire was collapsing under enormous political, military, social and demographic pressures. The Spanish invasion and devastating diseases brought enormous disruption and loss to communities throughout the once vast Inca Empire. Yet Machu Picchu remained isolated, high among the mountains, gradually disappearing beneath thick vegetation, clouds, rain and mountain mist. For centuries, seasons passed as rain, wind, sunlight and dense vegetation slowly covered more of the abandoned mountain settlement. Yet beneath the growing plants and weathered surfaces, many of the precisely fitted granite stones remained firmly locked together. Machu Picchu endured as a remarkable monument to the sophisticated engineering, architecture and construction knowledge developed by the Inca civilisation. But above all, the city remains a tribute to the thousands of ordinary people whose physical labour made its construction possible through incredible skill, patience, planning, teamwork and human strength, they transformed a remote Andean mountain ridge into something extraordinary. Their work created Machu Picchu, an enduring monument to human ingenuity and one of the ancient America's greatest engineering achievements.