The wealth and sophistication of the legendary Inca people lured many anthropologists and archaeologists to the Andean nations in a quest to understand the Inca's advanced ways and what led to their ultimate demise. Opulent wealth To imagine oneself living in the world of the Inca, one would have to travel back 500 years into a magnificent society made up of more than 10 million subjects. Cuzco, which emerged as the richest city in the New World, was the center of Inca life, the home of its leaders. "The riches that were gathered in the city of Cuzco alone, as capital and court of the Empire, were incredible," says an early account of Inca culture written 300 years ago by Jesuit priest Father Bernabe Cobo, "for therein were many palaces of dead kings with all the treasure that each amassed in life; and he who began to reign did not touch the estate and wealth of his predecessor but .... built a new palace and acquired for himself silver and gold and all the rest."

Money existed in the form of work—each subject of the empire paid "taxes" by laboring on the myriad roads, crop terraces, irrigation canals, temples, or fortresses. In return, rulers paid their laborers in clothing and food. Silver and gold were abundant, but only used for aesthetics. Inca kings and nobles amassed stupendous riches which accompanied them, in death, in their tombs. But it was their great wealth that ultimately undid the Inca, for the Spaniards, upon reaching the New World, learned of the abundance of gold in Inca society and soon set out to conquer it—at all costs. The plundering of Inca riches continues today with the pillaging of sacred sites and blasting of burial tombs by grave robbers in search of precious Inca gold. While some remnants of the Inca's riches remain intact, many were destroyed as looters melted them down for their raw metal. © Eduardo Mariano Rivero/iStockphoto Growth of an Empire The first known Incas, a noble family who ruled Cuzco and a small surrounding high Andean agricultural state, date back to A.D. 1200. The growth of the empire beyond Cuzco began in 1438 when emperor Pachacuti, which means "he who transforms the earth," strode forth from Cuzco to conquer the world around him and bring the surrounding cultures into the Inca fold. Consolidation of a large empire was to become a continuing struggle for the ruling Inca as their influence reached across many advanced cultures of the Andes. Strictly speaking, the name "Inca" refers to the first royal family and the 40,000 descendants who ruled the empire. However, for centuries historians have used the term in reference to the nearly 100 nations conquered by the Inca. The Inca state's domain was unprecedented, its rule resulting in a universal language—a form of Quechua, a religion worshipping the sun, and a 14,000 mile-long road system criss-crossing high Andean mountain passes and linking the rulers with the ruled. Referred to as an all-weather highway system, the over 14,000 miles of Inca roads were an astonishing and reliable precursor to the advent of the automobile. Communication and transport was efficient and speedy, linking the mountain peoples and lowland desert dwellers with Cuzco. Building materials and ceremonial processions traveled thousands of miles along the roads that still exist in remarkably good condition today. They were built to last and to withstand the extreme natural forces of wind, floods, ice, and drought. This central nervous system of Inca transport and communication rivaled that of Rome. A high road crossed the higher regions of the Cordillera from north to south and another lower north-south road crossed the coastal plains. Shorter crossroads linked the two main highways together in several places. The terrain, according to Ciezo de Leon, an early chronicler of Inca culture, was formidable. By his account, the road system ran "through deep valleys and over mountains, through piles of snow, quagmires, living rock, along turbulent rivers; in some places it ran smooth and paved, carefully laid out; in others over sierras, cut through the rock, with walls skirting the rivers, and steps and rests through the snow; everywhere it was clean swept and kept free of rubbish, with lodgings, storehouses, temples to the sun, and posts along the way."

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The beginning of the end With the arrival from Spain in 1532 of Francisco Pizarro and his entourage of mercenaries or "conquistadors," the Inca empire was seriously threatened for the first time. Duped into meeting with the conquistadors in a "peaceful" gathering, an Inca emperor, Atahualpa, was kidnapped and held for ransom. After paying over $50 million in gold by today's standards, Atahualpa, who was promised to be set free, was strangled to death by the Spaniards who then marched straight for Cuzco and its riches. Ciezo de Leon, a conquistador himself, wrote of the astonishing surprise the Spaniards experienced upon reaching Cuzco. As eyewitnesses to the extravagant and meticulously constructed city of Cuzco, the conquistadors were dumbfounded to find such a testimony of superior metallurgy and finely tuned architecture. Inca walls show remarkable craftsmanship. The blocks have no mortar to hold them together yet stay tight because of their precise carving and configuration. © Bartosz Hadyniak/iStockphoto Temples, edifices, paved roads, and elaborate gardens all shimmered with gold. By Ciezo de Leon's own observation the extreme riches and expert stone work of the Inca were beyond belief: "In one of (the) houses, which was the richest, there was the figure of the sun, very large and made of gold, very ingeniously worked, and enriched with many precious stones....They had also a garden, the clods of which were made of pieces of fine gold; and it was artificially sown with golden maize, the stalks, as well as the leaves and cobs, being of that metal....Besides all this, they had more than twenty golden (llamas) with their lambs, and the shepherds with their slings and crooks to watch them, all made of the same metal. There was a great quantity of jars of gold and silver, set with emeralds; vases, pots, and all sorts of utensils, all of fine gold....it seems to me that I have said enough to show what a grand place it was; so I shall not treat further of the silver work of the chaquira (beads), of the plumes of gold and other things, which, if I wrote down, I should not be believed." Machu Picchu and Living at Heights What remains of the Inca legacy is limited, as the conquistadors plundered what they could of Inca treasures and in so doing, dismantled the many structures painstakingly built by Inca craftsmen to house the precious metals. Remarkably, a last bastion of the Inca empire remained unknown to the Spanish conquerors and was not found until explorer Hiram Bingham discovered it in 1911. He had found Machu Picchu, a citadel atop a mountainous jungle along the Urubamba River in Peru. Grand steps and terraces with fountains, lodgings, and shrines flank the jungle-clad pinnacle peaks surrounding the site. It was a place of worship to the sun god, the greatest deity in the Inca pantheon. The survival of Machu Picchu over hundreds of years, on a mountaintop subject to erosion and mudslides, is a testament to Inca engineering. © Bartosz Hadyniak/iStockphoto Perhaps most unique about Inca civilization was its thriving existence at altitude. The Incas ruled the Andean Cordillera, second in height and harshness to the Himalayas. Daily life was spent at altitudes up to 15,000 feet and ritual life extended up to 22,057 feet to Llullaillaco in Chile, the highest Inca sacrificial site known today. Mountain roads and sacrificial platforms were built, which means a great amount of time was spent hauling loads of soil, rocks, and grass up to these inhospitable heights. Even with our advanced mountaineering clothing and equipment of today, it is hard for us to acclimatize and cope with the cold and dehydration experienced at the high altitudes frequented by the Inca. This ability of the sandal-clad Inca to thrive at extremely high elevations continues to perplex scientists today.

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The Conquest How did Pizarro and his small army of mercenaries, totaling less than 400, conquer what was becoming the world's largest civilization? Much of the "conquest" was accomplished without battles or warfare as the initial contact Europeans made in the New World resulted in rampant disease. Old World infectious disease left its devastating mark on New World Indian cultures. In particular, smallpox spread quickly through Panama, eradicating entire populations. Once the disease crossed into the Andes its southward spread caused the single most devastating loss of life in the Americas. Lacking immunity, the New World peoples, including the Inca, were reduced by two-thirds. With the aid of disease and the success of his initial deceit of Atahualpa, Pizarro acquired vast amounts of Inca gold which brought him great fortune in Spain. Reinforcements for his troops came quickly and his conquest of a people soon moved into consolidation of an empire and its wealth. Spanish culture, religion, and language rapidly replaced Inca life and only a few traces of Inca ways remain in the native culture as it exists today. Indigenous people of Peru today retain some echoes of the Inca way of life, but most of the culture has vanished. © Bartosz Hadyniak/iStockphoto

Editor's Notes This feature originally appeared on the site for the NOVA program This feature originally appeared on the site for the NOVA program Ice Mummies