Archaeologists have determined that the construction of Machu Picchu began about 1450, and the city, which had about 200 stone structures, was occupied for a century. But who lived at Machu Picchu and why it was built are still the subject of debate. Many experts believe it was a royal estate and religious center for the Inca ruler and his family.
The fine workmanship in some of the buildings, along with features such as private gardens and a bathroom, suggests that at least one group of dwellings was occupied by nobles. Experts say a permanent population of about 300 residents probably swelled to 1,000 or so when the royal entourage was in residence.
To embellish the scene, Healy had to find authoritative information on local food and vegetation, building structures, farming techniques, modes of dress, social customs, ceremonial rites, and many other aspects of Inca culture. When was maize harvested? What color were the local alpaca and llamas? What did orchids of the region look like, and were they in bloom in June?
A number of scholars and other Inca specialists were critical consultants to the mapmaking team.
Ruth and Kenneth Wright, of Boulder, Colorado, provided expert advice on the structural aspects of Machu Picchu, based on studies they've done at the site over the past eight years in cooperation with Peruvian archaeologist Alfredo Valencia Zegarra.
The Wrights share the admiration of the Inca expressed by the editor of National Geographic in 1913, who commented on a report in the April issue by Hiram Bingham on his discovery of the Machu Picchu ruins: "What an extraordinary people the builders of Machu Picchu must have been to have constructed, without steel implements, and using only stone hammers and wedges, the wonderful city of refuge on the mountain top."
A hydrological engineer with Wright Water Engineers, Inc., Kenneth Wright has written Machu Picchu: A Civil Engineering Marvel (ASCE Press, 2000) and many other published reports on the infrastructure of the prehistoric city. Ruth, a lawyer with a special interest in city planning, recently wrote The Machu Picchu Guidebook (Johnson Books, 2001), which contains a highly detailed site map of the ruins.
The couple's interest in Machu Picchu began in 1974, when Ruth first visited the Inca landmark with their two daughters. She was puzzled by how the Inca were able to obtain water for daily needs on such a high mountain ridge.
She posed the question to Kenneth after returning home, and "we vowed to go back and explore," Ruth said in a telephone interview. They tried for 20 years to get a government permit to study the prehistoric water supply of Machu Picchu, but were unsuccessful. Finally, in 1994, they obtained permission.
Since then they've returned to the site a dozen times to do in-depth research on paleohydrology, the drainage system, agricultural production, building foundations, and other aspects of the infrastructure. About 60 percent of the construction effort put into Machu Picchu is unseen because it is underground.
The Wrights work closely with local archaeologists and government personnel. "They do the archaeology and we do the technical work," Kenneth said.
National Geographic sought the couple's expertise to help fill in a major blank on the illustration: What did the roofs of the original buildings look like? The stone walls have survived in good condition, but the thatch roofs are gone.
"The Wrights stood at the site and took close-up photographs of every building, taken from the same perspective as the illustration, so the artist would have that level of detail to work with," said Healy.
Based on photographs, close-up observations, and engineering calculations, the Wrights made a map showing the exact location of every building at the site and what type of roof it would have had. They identified five different styles, based on clues that came from details such as receptacles for beams in the walls, patterns of alignment, even drip channels cut into the rocks to collect water dripping off of roof overhangs.
They determined that some buildings were designed to have no roofs and others had been left unfinished when the site was abandoned.
The Wrights visited the site last July and December to compare the working illustration with actual features of the ruins and the surrounding region.
They continuously reported their findings to Giusti, who was drawing the elaborate illustration. At one point, they measured the angle of the roof gables at Machu Picchu and advised the artist to make them steeper. The couple also concluded that the thatch of the roofs needed to be thicker than Giusti had depicted it.
Healy, meanwhile, was still in close communication with Inca scholars checking details for accuracy.
As the verification process continued and the artwork neared completion, Giusti had to adjust many intricate details. The clothing and haircuts of some workers in the illustrated scene had to be changed, for example, when the team realized the figures were shown in clothing that would have been worn exclusively by the nobility.
Kenneth Wright said the experience of working on the map gave him an admiration for National Geographic's exacting standards. "I was very impressed by the level of attention to detail and accuracy," he said.
"People need to realize," he added, "that this is as accurate a portrayal [of Machu Picchu] as is humanly possible."
The new Inca map, with a detailed illustration of ancient Machu Picchu, will appear in the May issue of National Geographic magazine, mailed to all members of the Society worldwide and available on newsstands in the United States beginning in mid-April.
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