In celebration of the ten-year anniversary of Paul Salopek's first steps on his Out of Eden Walk journey, this dispatch is now available for educational use in fifth- and eighth-grade reading levels. The original text is available as the default reading level, as well as on the Out of Eden Walk website.

This article is part of a collection called Out of Eden 10th Anniversary: Water. It is also included in the idea set, Exploring Water With the Out of Eden Walk.

By Paul Salopek

BADAI-TUGAI NATURE RESERVE, UZBEKISTAN (8/30/2016)

Following the banks of the fabled Amu Darya, antique highway of Alexander the Great and Genghis Khan.

The Amu Darya springs from the glaciers of the Pamirs and dies more than 1,500 miles to the west, in the human-made desert of the Aral Sea basin. The river’s currents carry the bone dust of empires. They are the color of sand.

During the conquest of Bactria in 329 B.C., Alexander ferried his whole army across the stream in five days, using bladders stitched from his troops’ leather tents. The Chinese monk and scholar Xuanzang crossed the Amu Darya on his 15,000-mile trek through the Buddhist world of the seventh century A.D. Genghis Khan shaped the river into a weapon of war in the Middle Ages—building and puncturing mud dams to flood the Silk Road kingdoms along its banks. This summer, with two guides, a horse and cargo donkey, I walked 220 miles of the Amu Darya’s main channel in remote western Uzbekistan. The waterway was no longer the superhighway it was in antiquity. It was an oxbow in time. It was a maze of channels, canals, reservoirs, dikes, embankments.

“We compete with the farmers for water,” said Oljabay Shaniyazov, director of the Badai-Tugai Nature Preserve, near the town of Nukus. “Cotton and rice takes priority. We pump water for our trees whenever we can.”

Shaniyazov’s trees: 29,000 acres of river poplars with stringy grey bark braided like old ship’s ropes. The trees are a remnant of immense woodlands that once shaded the Amu Darya’s wide bed for hundreds of miles. The local Caspian tigers are gone. But the preserve still shelters the country’s last herd of Bactrian deer. A young zoologist fed the exuberantly antlered beasts every morning as if they were his poodles. Behind him, the surface of the Amu Darya shone through the gnarled tree trunks like a steel scimitar unsheathed. Forest rangers couldn’t recall the last time a foreigner had camped in the park.

If the Amu Darya makes any headlines today, they usually concern the Aral Sea disaster.

Sixty years of irrigation projects under the Soviet Union, built to make the Central Asian desert bloom with cotton, have strangled the historic waterway. Today the Amu Darya evaporates miles before reaching its old delta in the Aral Sea. Independent Uzbekistan has inherited the fourth-largest saltwater lake in the world as a graveyard of sand dunes, fish bones, dust storms, and beached ships. The Aral’s shoreline retreats every year in rhythmic ebb tides. Its dregs are so salt-dense it is impossible to submerge in them.

The Amu Darya is largely a course of ghost waters. Walking connected what is and what was.

With guides Aziz Khalmuradov and Tanatar (“Bolt of Sunrise”) Bekniyazov, I slogged from Kungrat to Khiva on a quilt of canal roads. The entire world traveled them. Shepherds piloting unruly herds of tree-climbing goats. Women melon farmers wearing face masks against suntan. Three schoolboys pumped by on bicycles, each in a white ball cap emblazoned F.B.I. The river people—ethnic Karakalpaks mainly, but also Uzbeks, Turkmen, Kazakhs—were friendly but shy. Beehive ovens puffed smoke in their yards. Villages bore rough pioneer names like Three Roofs or Five Roofs. We camped in apricot orchards. When the canal paths dead-ended in water, we swam.

Even tamed by agriculture, the lower Amu Darya still holds a dizzying magic. Time pools.

Downstream from the nature preserve stood two giant mud fortresses. One, Gaur Kala, dated back two millennia and was Zoroastrian. The other, Jampik Kala, was built in the 11th century by the Muslim trading empire of Khwarezm. (The Mongols destroyed both.) The ruins would have been swarmed by tour buses in some countries. On the Amu Darya, old men played backgammon under their lonesome ramparts without ever glancing up.

Another day’s walk downstream, at a place called Chalpyk, we climbed a 2,200-year-old Tower of Silence where fire worshippers had placed their dead on scaffolds to be stripped by birds. The temple looked like a volcano knuckling up from the desert plain. From its summit poked a modern surveying marker—a steel tripod. People had wrapped it in ribbons of rags, converting it into a wishing tree. The Amu Darya was like this.

“I must admit myself that, as far as my experience of water extends, I have never found a river or source that yielded any so precious as that of the Oxus,” wrote Arminius Vámbéry, a Hungarian explorer who marched along the Amu Darya in 1863, calling the Amu Darya by its classical Greek name, the Oxus.

Vámbéry was slippery character: disguised in the rags of a Sufi pilgrim, he spied for Britain during the jockeying between London and imperial Russia for influence over Central Asia’s hermetic khanates—a 19th-century version of the Cold War dubbed the Great Game. On the topic of the Amu Darya’s waters, however, Khalmuradov, Bekniyazov and I felt the same.

We walked from hand-pumped well to hand-pumped well. We walked from eddy to eddy.

At a pumping station we sipped tea with engineers who told of hooking the bodies of sozzled fishermen from the river. They spoke of river ice so thick you could drive your car across to Turkmenistan in winter, and they talked of catfish so big in the sand-colored waters that it would require a tractor to haul them out. And in the moonlight one night I walked hot and filthy and fully clothed into the Amu Darya—the airborne dust raked up from the dying Aral Sea, scientists say, is accelerating the melting of the Tajik glacier fields that birth the stream—and let its tired fingers pick me up, spin me around, and cradle me.