Merv is what is left of a city that once argued with Baghdad about which of them was the greatest in the Muslim world. Today it lies as a wide spread of mud-brick walls, domes and mounds in the Karakum desert of Turkmenistan, a few kilometres from the town of Bayramaly and not far from the regional capital Mary. The Murgab river fans out here into an oasis, and for more than two thousand years that thin green strip made Merv the natural halt on the Silk Road between Persia and Central Asia.
There is not one Merv but several, laid side by side as each new ruler built next to the old. The oldest walls, Erk Kala, go back to the Achaemenid era. Alongside stand Gyaur Kala of the Sasanian and early Islamic age, and the later Sultan Kala, the capital of the Seljuk sultans in the eleventh and twelfth centuries. The mausoleum of Sultan Sanjar is the building most visitors cannot miss, a big brick cube that was once crowned by a double dome and has been a landmark in the flat plain for nearly nine hundred years. Then came 1221, when Mongol forces took the city and killed a huge share of its people, a blow from which Merv never fully recovered. Kyz Kala, the smaller fortified buildings with their ribbed mud walls, are the ones that look best in low light.
Treat the ride as an expedition rather than a joyride. Turkmenistan requires foreign travellers to arrange visas and often permits, and motorcycle entry takes planning ahead, so do the paperwork long before you arrive. The roads across the Karakum are flat, long and straight, with heat above forty degrees in summer and a wind that carries sand across the tarmac. Spring and autumn are far kinder. Fuel is strikingly cheap in this country, but stations are spread out, so fill up in Mary or Bayramaly and carry water.
At the site, the ground is dust and fragments of glazed pottery, and the best hour is early or at sunset when the brick turns gold. Take shade, go slowly, and look for the wind-carved edges where whole streets are buried only a metre down.