Saturday, February 18, 2017

Pueblo Bonito and Chetro Ketl

Pueblo Bonito
1 mile loop, 50 feet elevation gain
Difficulty: Easy
Access: Poor dirt road to Chaco Culture NHP; Chaco Culture NHP entrance fee required

In the remote reaches of the New Mexico high desert, on the flat floor of a sandstone canyon hours from the nearest cities or towns, lies the heart of one of the great and advanced civilizations of precontact America. Here, amongst the saltbrush and arroyos, stand the remnants of magnificent public houses acres in size and five stories tall; for centuries, this was the beating heart of the Ancestral Pueblo civilization, the political and cultural nexus for the tens of thousands of their people spread over what is today the Four Corners. Here lies one of the most forgotten wonders of our world: the grandest architectural statements north of Mexico, with apartment blocks, great kivas, and wide plazas built by a people with a deep knowledge of the sun and the stars. This is Chaco Canyon, one of the most undeniably significant archaeological sites in the country.

Of all the great houses of Chaco, Pueblo Bonito stands out due to its meticulous construction, its extraordinary collection of artifacts, its high degree of preservation, its beauty, and its size: at the time of its discovery, the footprint of this great house, built over three centuries starting around 850 AD, was larger than that of the US Capitol in Washington DC. Chetro Ketl is the second most impressive of the Chaco great houses, with a large great kiva and a collection of rooms surrounding large elevated kivas. This short, one mile hike visits both houses and provides the incredible experience of walking through Chacoan rooms in Pueblo Bonito; it is the undeniable highlight of any visit to this UNESCO World Heritage Site.

I visited Pueblo Bonito and Chetro Ketl on a trip out to Chaco Culture National Historical Park, which preserves all twelve great houses and countless villages and dwellings in Chaco Canyon. The park is a three hour drive from Albuquerque; the easiest way to reach it is to take US 550 northwest from Bernalillo, turning left at Road 7900 just past the Red Mesa gas stop a few miles before reaching Nageezi. Signs directed me to the park from US 550, taking me first down a nice paved road (Road 7900) and then down a decent gravel road (Road 7950) that then turned into a bumpy, washboarded dirt road that required driving through a wash. During dry weather, the road is probably doable for most vehicles, though it is not an easy drive; if water in the wash is high, the park may be inaccessible. The road became paved again at the park entrance; I turned right for the Park Loop Road just past the visitor center and followed the one-way road out to the Pueblo Bonito parking lot.

Visiting close to sunrise or sunset can give an opportunity to see spectacular colors on the great houses. However, it's important to note that the Park Loop Road closes at sunset and that this closure is strictly enforced by the National Park Service; visitors who remain in the area after sunset may be ticketed. I also recommend budgeting plenty of time, especially if you appreciate architectural detail or history; I spent about 100 minutes doing this hike and still felt rushed.

Two trails led away from the parking lot: the left fork towards Pueblo Bonito, the right fork towards Chetro Ketl. I took the right fork and first visited Chetro Ketl. The trail passed by the indistinct outer wall of the great house and entered the large central plaza. The first section of wall that I got to observe from the trail was also one of the most interesting: here, the south-facing wall was clearly built with either large windows or square columns; archaeologists consider this the only colonnade in Chaco Canyon. As columns are otherwise absent in Pueblo architecture but was a feature of Mesoamerican architecture, it's likely that the construction here was influenced by styles over a thousand miles to the southeast.

Colonnade at Chetro Ketl
The trail also offered a chance to look down into some deeply excavated rooms, which was effective at conveying the fact that Chetro Ketl must have been a multistory structure and that current ground level is probably above the ground level of Chetro Ketl during its period of use.

Continuing past the colonnade wall, the trail turned back into the central plaza and came to the great kiva of Chetro Ketl. This kiva is very large, second only to the kiva at Casa Rinconada in size at Chaco Canyon. Kivas were community gathering spaces that likely served ceremonial and religious functions. This particular great kiva looked particularly impressive, though the completeness of the kiva walls and interior suggested that this particular kiva must have been partially reconstructed.

Great Kiva of Chetro Ketl
Past the great kiva, the trail passed by a set of smaller kivas in Chetro Ketl's southeast corner, then wrapped around to follow the north wall of the house.

Construction of Chetro Ketl began around 990 AD, after hundred of years of human habitation in Chaco Canyon and a century and a half after construction began on Pueblo Bonito, and took most a century to complete. Chetro Ketl's footprint is the largest of any Chaco great house, although at three acres it is very similar in overall size to Pueblo Bonito. However, Chetro Ketl lacks the shear number of rooms built at Pueblo Bonito; there are about 400 rooms in Chetro Ketl, which was likely up to four stories tall. The lack of plentiful artifacts at Chetro Ketl and the relatively small amount of refuse generated suggest that despite its size, Chetro Ketl may not have been densely inhabited.

Theories regarding Chetro Ketl's role in the Chaco world mirror theories regarding the canyon's place in the Ancestral Pueblo civilization. Undoubtedly, Chetro Ketl and Pueblo Bonito wielded power and influence broadly recognized throughout the San Juan Basin. Archaeologists and anthropologists have offered theories as to whether that power was religious, political, or both; most park literature introduce Chetro Ketl and Pueblo Bonito as centers for pilgrimmage from the villages in the orbit of the Chaco culture. Artifacts collected in the great houses have been interpreted as having ritualistic value, based off knowledge of similar items used today by the modern Pueblo peoples. It's very likely that these great houses were endued with some religious significance. Chetro Ketl and Pueblo Bonito were also the center of a trade network: turquoise and corn cobs traced to locations throughout the San Juan Basin were excavated from these houses. Chaco-style ceramics were exported, as Chaco designs have been found throughout outlying Pueblo settlements. Although current interpretations of Chaco suggest that the great houses served a mainly ceremonial purpose, past anthropological interpretations have suggested that Chetro Ketl and Pueblo Bonito might have formed the hub of power in a Pueblo state encompassing the San Juan Basin. As the Ancestral Puebloans had no written language outside of their pictographs and petroglyphs, there's no written record from which to understand Chaco's role in their civilization.

The trail finished its tour of Chetro Ketl by following the long north wall of the great house, which offered glimpses through windows to see the many rooms and the tower kiva in the house's interior.

Chetro Ketl window
Tower kiva at Chetro Ketl
Leaving Chetro Ketl, I came to the Talus unit, a small pueblo built at the base of Chaco Canyon's north wall. This pueblo had a number of kivas and some reasonably well-preserved masonry.

I continued past the Talus unit on the Petroglyph Trail, which connects Chetro Ketl with Pueblo Bonito; this trail followed the base of the canyon wall, rather than returning to the parking area. In the next third of a mile, I walked at the foot of impressive sandstone cliffs, gazing up occasionally at precarious columns of rock that seemed like they might tumble any time. At eye level, the canyon walls were dotted with petroglyphs carved into the sandstone by the Pueblo people a millenium ago.

Petroglyphs along the cliff between Chetro Ketl and Pueblo Bonito
The Petroglyph Trail ended by joining the wide path circling around the northeast side of Pueblo Bonito. At this junction, I took the right fork, which made its way through a massive jumble of fallen boulders and came to a platform atop a large boulder overlooking Pueblo Bonito.

Standing atop the viewpoint and gazing out over the remains of Pueblo Bonito, I was overcome with awe: spread out before me was a maze of rooms, walls, kivas, and plazas constructed of extraordinary masonry. The site's name, given by a US military unit that surveyed the area in 1849 after the Mexican-American War, translates to beautiful town; this vastly understates the extraordinary nature of Bonito.

The outer walls of the northeastern part of Pueblo Bonito are destroyed, having been crushed by a rockfall in 1941 by the collapse of Threatening Rock, once part of the canyon's north walls.

Pueblo Bonito
Multiple excavations over a century, starting with those by homesteader and amateur archaeologist Richard Wetherill, have uncovered a wealth of artifacts at Pueblo Bonito. These finds suggested that the residents of the Pueblo were either extremely wealth or yielded enough religious or political power to collect goods traded from far away. Rooms at Bonito held turquoise from Cerrillos (near Santa Fe), macaw feathers from Mexico, and pottery with traces of chocolate, which could only have been imported from Central America.

Wetherill discovered the famous Cliff Palace of Mesa Verde before conducting his excavations at Pueblo Bonito. Wetherill had the unfortunate habit of selling many of the artifacts that he excavated as souvenirs, a practice he shared with Gustav Nordenskiold, a Swedish explorer who taught Wetherill excavation techniques at Mesa Verde and who sent crateloads of Pueblo artifacts off to Europe. The practices of Wetherill and Nordenskiold- only part of the late nineteenth-century American custom of looting Ancestral Puebloan sites- sparked Congress to pass the Antiquities Act in 1906, giving the president authority for swift, unilateral action to protect areas of historical or scientific significance. Chaco Canyon National Monument, the precursor to the current Chaco Culture NHP, was one of the first monuments established by Theodore Roosevelt under the authority granted to him by the Antiquities Act.

Wetherill also bestowed the name "Anasazi" upon the people who built the pueblos of Chaco and Mesa Verde. Although commonly used as an academic term for the good part of a century, the name Anasazi has recently been abandoned for the term Ancestral Puebloans; Anasazi, after all, is a Navajo word that means "ancestors of our enemies." Often introduced to these ancient pueblos by the Navajo, Wetherill adopted their unflattering name for the people who built these structures. The Navajo name in turn comes from the rocky relationship between the Navajo and modern Pueblo peoples. While the modern Pueblo peoples are descended from the ancestral Puebloans, the Navajo are latecomers, nomadic peoples related to the Dene of the Canadian Great Plains and Alaska who arrived in the Southwest around the 15th century; the Navajo settled into the abandoned homelands of the Pueblo people and occasionally came into conflict with the Pueblo people. While Chaco was built by the Ancestral Puebloans, it has been part of the landscape inhabited by the Navajo for the past few centuries; the Navajo Nation lies just west of the park. Archaeologist Stephen Lekson noted the antipathy between the Pueblo and the Navajo when recounting an attempt to include Native American input in the Chaco Project, the last large scale excavation at Chaco: Pueblo people tried to exclude Navajo from providing input on the future of sites that the Pueblo claimed as their heritage, while the Navajo refused to be excluded from discussions about sites that lay in what is now the Navajo homeland.

Outer walls of Pueblo Bonito
Pueblo Bonito is roughly shaped like the letter D, with the rounded section of the building pointed north. The trail circled around much of the tall, semicircular northern wall of the building before entering through a gap in the wall. These walls reach up to five stories tall, indicating that the multistory construction at Pueblo Bonito at least led to the construction of masonry structures with five floors. To support the load of five floors, many of the walls at Pueblo Bonito are extremely thick: in some spots, the base of the walls are up to four feet wide. The walls taper off in thickness higher up, with the masonry walls just a foot thick on the fifth story.

Pueblo Bonito
A short spur trail led through one of the oldest parts of the building. The construction of Pueblo Bonito began around 850 AD, around the same time as the great house of Una Vida up the canyon; this far precedes the construction of the other great houses at Chaco and elsewhere throughout the Pueblo world. Bonito was built in several phases: the rest of the great house is effectively extensions built on this initial structure. The masonry in this older corner is notably poor, requiring much more frequent use of mortar than other spots in the great house that exhibit superb masonry. The sandstone making up the walls of all of the Chaco great houses were chiseled off the sandstone walls of the canyon.

Continuing on the, the trail brought me into the huge central plaza at Chaco. Two great kivas here were smaller than the great kiva at Chetro Ketl but were still over 50 feet in diameter and could have held hundreds of people during the Golden Age of Chaco.

Great Kiva of Pueblo Bonito
From the plaza, one trail led directly out the south wall of the complex and back to the parking lot. I did not follow that trail, instead taking the trail that headed to the left, climbing up a few stairs to a walkway elevated between four medium-sized kivas. From here, the trail then dropped down to an entrance into one of the rooms.

The last stretch of the path through Pueblo Bonito involves walking through 12 rooms in the complex and is one of the highlights of the hike; however, it does require passing through low doors, meaning most people will have to duck or crawl to go between rooms.

Multistory construction of Pueblo Bonito
One of the more interesting aspects of the Pueblo Bonito rooms are the wooden beams that served to separate different floors. In Chaco architecture, ceilings are floors were made from spaced-out wide wooden beams known as vigas covered with densely packed latillas, or smaller wooden beams. All of Chaco's 800 or so rooms were built with this roof structure. In each room, it's possible to see the many layers of vigas, each indicating an additional floor of Pueblo Bonito. In one room, the vigas and latillas were left intact during excavation and form the only remaining publicly visible ceiling in Chaco today.

These wooden beams were critical in helping archaeologists date Pueblo Bonito. Using dendrochronology, archaeologists match up tree ring patterns from the wooden beams with a known tree ring record for the Southwest that reflects yearly fluctuations in climate. Dendrochronology was critical in first establishing that Bonito's age and was used to trace the fact that construction of the full great house took nearly 300 years.

Where did the Ancestral Puebloans source so many wooden beams in the middle of a desert canyon with just a handful of cottonwoods? The answer lies 50 miles west of the canyon: the forested Chuksa Mountain supplied up to 200,000 trees for construction of Chaco's great houses. To me, this is one of the most stunning aspects of Chaco civilization: in a society with no domesticated livestock, human laborers transported hundreds of thousands of ponderosa pine through the desert to this dry, remote canyon to build magnificent structures. It seems impossible to me that this could have accomplished without strong societal organization and a large population. Interestingly, Pueblo Bonito itself, despite its size, is not believed to have housed many residents: although early archaeologists estimated the pueblo to be a city of over a thousand residents, more recent analyses point to the lack of hearths in the building to argue that most rooms were likely not residential and that the population of Bonito itself may have been only around one hundred.

Even if Pueblo Bonito itself was not heavily residential, Chaco Canyon itself likely supported a population of thousands, if not ten thousand, scattered throughout small villages and unit pueblos in the canyon. Although climate differences and advanced irrigation techniques probably allowed Pueblo farmers to turn the valley floor into productive agricultural land, much of the food at Chaco was still imported, with corn coming from as far away as the Chuksa Mountains. Chaco's influence reached to at least two hundred other great houses and villages in the Southwest, including the Ancestral Puebloan cultures at Salmon, Aztec, Lowry Pueblo, and Chimney Rock. While the true nature of political connections between Chaco and these outlying pueblos is unclear, the collective population of these related cultures was at least 20,000-30,000; I personally still find it amazing, if hard to believe, that a civilization with a population of only 30,000- less than that the population of Charlottesville- could have provided the manpower and planning necessary to build the Chaco great houses.

Corner window at Pueblo Bonito
One of the last notable architectural features on the Chaco walking tour was a corner door, a unique door that opened simultaneously on four rooms. Corner doors are fairly rare in Chaco, but many of the existing corner doors were built as astronomical markers. The ancient culture at Chaco had a deep knowledge of astronomy, incorporating features of astronomical significance into their building plans.

In fact, Chaco came to my attention due to the astronomical knowledge of the Ancestral Puebloans: Carl Sagan introduced their scientific feats in his TV series Cosmos. The Ancestral Puebloans tracked the sun, moon, and stars carefully: the most famous of their astronomical markers is the Sun Dagger petroglyph on Fajada Butte, near the Chaco Culture NHP visitor center. There, light passing through slits between three rocks pass over the center of a spiral petroglyph only at noon on summer solstice.

By the early 13th century, the people of Chaco were beginning to leave. After reaching its heyday in the 12th century, the canyon was completely abandoned by the Ancestral Puebloans a century later. The causes of this migration are not completely clear, although theories include a move forced by drought or climate change and a retreat from violent clashes with newly arrived nomadic peoples. In either case, the people of the Chaco world dispersed in the 1200s, moving south and east to the Jemez Mountains, the Rio Grande valley, and the lands now held by the Zuni and Acoma Pueblos.

Some archaeologists have noted that this migration was not sudden: many great houses were boarded up before being abandoned, with windows and doors filled in. What happened to the high culture and civilization of the Golden Era at Chaco? Based on the walling off of doors with astronomical significance in Chaco and on fires set in some kivas at the time of abandonment, some anthropologists have speculated that perhaps changing climate or other conditions led to a backlash against the knowledge of the stars, ending that study in Chaco culture. Whatever the reason, Pueblo Bonito has now been abandoned for seven and a half centuries.

As the sun prepared to set, I said goodbye to the extraordinary Pueblo Bonito and followed the last two hundred meters of a wide gravel path back to my car.

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