Out on the edge of the Murghab oasis in south-eastern Turkmenistan, where irrigated cotton fields meet the sand of the Karakum, low mounds rise from the flat land. Tepe means hill, and these hills are the eroded remains of ancient settlements: Yaz Depe, which gave its name to an Iron Age culture of the early first millennium BC, and Gobekli Depe nearby. To an untrained eye they are just humps of clay, but they belong to one of the longest continuous stories of settlement in Central Asia.
The bigger story is Merv, a short ride away by Bayramaly. For more than two thousand years cities rose here one beside the other: the Achaemenid fortress of Erk Kala, the Hellenistic and Sasanian city of Gyaur Kala, and medieval Sultan Kala, whose giant mausoleum of Sultan Sanjar still stands with its brick dome against the sky. Merv was one of the great cities of the Silk Road until the Mongols destroyed it in the thirteenth century. Scattered across the fields are koshks, fortified mansions with corrugated walls that look like folded curtains, and the whole area is a World Heritage site.
Riding in Turkmenistan is unusual and needs planning. Foreign travellers usually need a visa tied to an itinerary, often a transit visa with fixed entry and exit points, and riding off approved routes can attract attention. The main roads from Mary to Bayramaly and on towards Turkmenabat are flat, straight and of variable quality, with sudden potholes, police checkpoints and heat shimmer. Side tracks to the tepes are dirt and dust. Spring and autumn are the seasons to come; summer temperatures in the Karakum are brutal.
The land is harsh but alive. In spring the desert edge turns briefly green, tortoises cross the tracks, and larks sing over the fields. Irrigation canals fed by the Murghab and the Karakum Canal keep the oasis lush, and lines of mulberry and poplar trees shade the roads.
Fuel in Turkmenistan is cheap, and Bayramaly and Mary both have stations, markets and simple restaurants serving plov, shashlik and fresh round bread. Mary is the main city of the region and has hotels. Carry plenty of water, cover your skin, and keep your documents at hand for checkpoints.