Today, we watch a lonely city die. 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.
The 7th-century Mayans
didn't have the wheel. They didn't have anything
like the mathematics that was already old in Europe
and Asia. And yet, during the next century, they
built the city of Coba in northeastern
Yucatán. The city covered 30 square miles
and was home for some 50,000 people. Until recent
centuries, that was the size of the great cities of
Europe -- Athens, Rome, Paris, and London.
The crowning glory of Coba is a 120-foot pyramid
rising out of the undergrowth. From its top you can
see 6500 mounds where the jungle has grown over its
buildings and buried them.
Another kind of structure catches our eye when we
look more closely. Fifty roads radiate from the
city. Actually, road is an odd word to use in a
land that never took up the wheel. These are stone
footpaths that reach as far as 60 miles through
flat jungle and swamp terrain. They express linkage
and connection for a highly civilized people more
than they express real need. Along these roads we
find ceremonial stones engraved to great people and
events. We also find toll booths.
Coba lasted 600 years. Finally, its people walked
away and let the jungle grow over it. They left 300
years before the Spanish invasions. They weren't
driven out; so what did happen?
The answer is that this great city wasn't the fruit
of great technology. It was instead a tribute to
organization and cooperation. The Mayans of Coba
were isolated from other advanced peoples. They
used what they themselves invented; but other
cultures didn't feed them with ideas. Without the
wheel, they didn't have pulleys -- no block and
tackle. They used less technology than the
Egyptians 4000 years before them. They made
majestic structures without the keystone -- without
geometry.
The lack of one technology in particular killed
Coba. The Mayans didn't know about crop rotation.
Agriculture was first invented in the Middle East
-- in a much harsher land. Those first farmers
learned to nurture the soil that nurtured them. But
the Mayans planted corn, over and over, on a
shallow bed of topsoil. In the end they killed the
earth. They drove themselves away.
The people of Coba did show us inventive genius. We
find traces in this abandoned city -- the idea of
an alphabet, of sewage disposal and plumbing, of
art, and of fish farming. What they lacked was
cultural mixing. They lacked an infusion of ideas
from other peoples and other lands. ¨What
really killed the city of Coba? It was the lack of
alien influence -- the strangers from across the
river -- people with different thoughts. Coba died
of intellectual isolation.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
