age of Islamic intellectual achievement. Asian
innovations like pulp paper, forged steel, and
early advanced mathematics rocked westward
to Europe atop camel trains. The Silk Road blew
open the mind of the Old World.
“To survive in this desert, you need farming,”
explained Gavkhar Durdieva, an architect in
Khiva. “To farm, you need to understand irri-
gation, and that requires engineering. We used
math to feed ourselves.”
With pride, Durdieva listed for me the Silk
Road geniuses who a millennium ago invented
the algorithm or calculated the radius of the
Earth. Yet Khiva today was a sepulchral city.
It was an artifact preserved under a bell jar.
Busloads of German tourists sipped cappuc-
cino under imposing stone ramparts that now
defended nothing from nothing.
Antique walls are a feature of the Silk Road.
For two years, I hiked past old battlements,
parapets, and bulwarks. While it’s true that such
medieval defenses kept armed nomads and
raiders at bay, the larger truth is that the rich,
multiethnic trading kingdoms of Central Asia
rotted from within. They succumbed to politi-
cal and religious polarization, to the chaos of
dynastic struggles, to sectarian fanaticism (the
Shiite-Sunni schism), intolerance, anti- rational
purges, and, ultimately, stagnation. By the 1200s,
Genghis Khan had walked right over them.
Walls were monuments to policy failure. Be
careful what you lock in.REMEMBER SAROJ
DEVI YADAV.
She wore a bright fuchsia scarf, and her right
foot was bandaged against a thorn puncture.
She lived on a farm in Rajasthan, India, about
10 miles east of Jaipur. Her fields of wheat shim-
mered under the sky, and there were buffalo
wallows of black mud. I’d been crossing suchA JOURNEY'S LESSONS 137