Today, we ask about permanence in a civilization. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.
Every region has its defining piece of architecture -- Egypt's Great Pyramid, Paris's Eiffel Tower, Rome's Coliseum. And the great pueblos of Mesa Verde conjure up the American Southwest.
Those huge cliff houses were, in fact, a very brief flash in the pan. We call their builders the Anasazi -- or the Ancient Ones. Around 350 BC, they moved into the four-corners region of Arizona, New Mexico, Utah, and Colorado. By AD 1300 they'd finally developed from hunting and gathering into a settled, house-building, agricultural society. Then they just disappeared.
By AD 550 the Anasazi were building pit houses, dug into the ground. They entered and left by ladders through a smoke hole in the roof. By AD 750 they were building one and two-story houses above ground. They became basket weavers, then fine potters.
They began building the multi-storied pueblos of Mesa Verde around AD 1200 -- the ones we see on every postcard from the area. One Mesa Verde house had 223 rooms. They built on a heroic scale.
By then, the Anasazi were conducting wide-ranging trade with other tribes. Their remains include shells from the Pacific coast, clays and wood from other regions. Their sophisticated technologies included complex decorative pottery and abstract petroglyphs.
But that last epic of building lasted less than three generations. Around AD 1250, the Anasazi were involved in a war against another tribe. They survived, but then, in 1276, a drought came. They'd weathered other droughts, but, by now, Anasazi life was turning weird. At the last, we find evidence of nasty human sacrifices. We also find people were beginning to leave.
By 1300 the exodus was complete. The last people left suddenly -- leaving beautiful pottery and other goods behind. The brief age of Anasazi greatness blew away like summer smoke. Did they run out of water or wood? Did they just lose their confidence? Did some mad prophet turn Mesa Verde into a crazy cult?
We don't know, but the story is not unique. It's been repeated all over the world, down through the ages. After Rome fell apart in the 5th century AD, Central European nomads and African camel trains moved among its abandoned architectural remains with no inclination to make use of them. Monuments have simply been left behind all the way from Easter Island to the rose-red city of Petra.
And so the great pueblos stood, isolated and unoccupied, protected by overhanging cliffs, for 700 years -- until the anthropologists finally came to puzzle over the mystery of impermanence.
It's unsettling that many great spurts of building actually signal instability rather than permanence. The Anasazi pueblos warn that civilization is held together by subtle and complex factors. In the end, it is much more than mere stone and mortar.
I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.
Much is written about Mesa Verde. Check out your encyclopedias, for example. I recommend a recent article in the popular press: Sopronyi, J.P., Mystery of the Ancient Ones: Colorado's Mesa Verde. Historic Traveler, March 1996, pp. 36-44, 73-74.
Mesa Verde, Colorado
Stereopticon Image courtesy of Margaret Culbertson