by Paul Salopek

Paul Salopek is walking the global trail of the first humans who migrated out of Africa in the Stone Age. His continuous 21,000-mile foot journey, called the “Out of Eden Walk,” is recorded in dispatches.

It is a tricky business, crossing the Caspian Sea by ship.

The Caspian is a fickle sea—her mood changes swiftly, like the color of her waters, from placid green, to stormy grey, to dangerous wind-raked white. This biggest of the Earth’s lakes—for the Caspian is truly a lake, and her vast waters, the size of Germany, are only a third as salty as the sea—make shipping unpredictable, a waiting game. Dockings and departures change. Schedules are revised. The freighters rock at anchor, waiting for gales to pass, waiting for a berth. And so, my bags are packed. And unpacked. And packed again. But Tural Aliyev, my friend at the Baku Port of Azerbaijan, assures me that today there will be a ship. And I believe him. Aliyev is always right. He is the man you want at dockside—the veteran hand with all the right connections, the savvy, the weather eye, and the private numbers of every captain and cargo handler in Azerbaijan.

“Be ready at midnight,” Tural tells me. “It is for real now.”

And indeed at midnight, I haul my mule’s old cargo bags, faded by the Turkish sun, up the gangway of the MV Fikret Emirov. I am sailing across the Caspian. I am bound for the coast of Kazakhstan. Soon I will begin walking toward China.

What is the MV Fikret Emirov? A Soviet-era cargo carrier. A roll-on/roll-off ship manufactured in 1985 in East Germany that has seen Caspian and Black Sea service. Her crew: Azeris, Russians, Turks. She transports trucks filled with cargo from the Caucasus to Central Asia and back: a rusty link in the modern Silk Road between Europe and Asia. I am shown to a barren cabin by a steward, a haggard blonde from the Urals named Irina. The ship hauls her lines at dawn. Steams out to sea. Turns around barely an hour later. Steams back to Baku Port. We have gone nowhere! We wait, dead in the water, for many hours.

For what?

It is impossible to know. It is a ghost ship.

The 28 Turkish truckers onboard are dozing—locked inside the cabins of their tied-down vehicles. The crew’s quarters are off-limits. The passageways are completely empty: uninhabited tunnels of steel, of plywood. Not a living soul stirs on deck. I sit in my cabin. The iron walls vibrate. The ship creaks, shudders, gasps. It is odd, after walking thousands of miles from Africa, to be paused at sea like this. To be cut-off, isolated. (My phone is useless.) To be trapped in a gigantic motorized box. (I cannot disembark; my Azeri exit visa is stamped.) The sun sinks into the distant brown plains of Azerbaijan. I float offshore, on the rippling surfaces of two liquids. (Air, water.) I bob in limbo between continents. I fall asleep.

It is pitch black when I wake. We are underway.

The ship, astonishingly, remains empty. I own its 140-yard length. I pace its lonesome, trembling rails. I look down at foam that spirals off the hull and against the charcoal waves like living marble. The Caspian. Home to the Persian merchant-sailors who shopped the beach bazaars for silks shipped to Venice. Home to Stepan Razin the 17th-century Cossack pirate. (The Tsar pulled his arms and legs out of their sockets, branded him, dripped ice water on his shaved head, fed his bowels to the dogs.) Home to vast subsea seas of gas, of oil. To the last wild sturgeon—source of black caviar. To unwashed Viking traders. To a merman who sings to fish.

The wind blows all night—a cold norther called the khazri. The same three seagulls draft on the superstructure all the way across the sea. I go inside. I come out hours later. I look up. The birds are there. They reach a new subcontinent without flicking a wing.