Today, a 2300-year-old wall. 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.
Sooner or later, any series
such as this must reach the Great Wall of China --
that cryptic, brooding snake, girdling a tenth of
Earth's circumference. The Great Wall is, in fact,
an array of shifting forms that spans millennia as
well as miles.
Walls are woven into Chinese culture. The shabbiest
village and the grandest city alike will boast a
wall. The first Great Wall was a
three-thousand-mile structure built of tamped
earth. It was begun under the whip of the
tyrannical emperor Qin, starting in 221 BC.
Qin's people built upon earlier pieces of the wall,
some of which had been in place for 150 years --
maybe longer.
The obvious purpose was to wall out northern
barbarians. But the repressive paranoia of the
regime suggests that Qin brought a great deal of
pure self-aggrandizement to the project. Qin also
built the underground terra cotta army of Xi-an.
And his wall was thirty times the length of
Hadrian's Wall -- built to keep northern invaders
out of England.
After Qin's death in 208 BC, his evil empire
collapsed. The far more humane Han dynasty
soon replaced it. The Hans lasted over four
centuries and left a huge technological legacy.
They gave us paper. Within two generations they'd
beaten back the northern invaders. Then they
extended the Wall still farther west, all the way
across the Gobi Desert. Of course, that merely
established its location. The Wall didn't yet have
its present appearance.
Down through the first millennium AD, various
dynasties built more pieces. The Wall now extends
from the Yellow Sea, across Northern China, below
Mongolia, and along a big stretch of the Old Silk
Road. It ends in what the Chinese called The
Last Gate of the World -- in Central Asia, on
China's far west border.
But the Wall we recognize came much later. It was
largely the work of the fourteenth-century
Ming dynasty. They were the civil engineers
who built the Wall to over thirty feet high. They
filled it with earth and faced it with brick or
stone. They built it wide enough to accommodate a
marching troop of soldiers. Theirs was the Wall
with watchtowers every hundred yards. By the time
the Ming dynasty was done, over 6300 miles of Wall
(with its many loops and digressions) sprawled
across northern China.
So what was the legacy of this vast effort? It
probably did serve the purpose of keeping invaders
out. But it was finished just as the new cannons
were being perfected. Artillery was about to put an
end to all great walls. A century ago, Robert Frost
looked at traditional New England wall-building,
and he mused upon its purposes. He said,
Oh, just another kind of out-door game;
...
Before I built a wall I'd ask to know
What I was walling in or walling out,
And to whom I was like to give offence.
Something there is that doesn't love a wall ...
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
