The Sultan Kala walls
Worn earth into the distance.
John Pavelka from Austin, TX, USA — CC BY 2.0 · Hans Birger Nilsen — CC BY-SA 2.0 · CC BY-SA 3.0 · Hans Birger Nilsen — CC BY-SA 2.0 · 13299achan — CC BY-SA 4.0
Ancient Merv is the site of a great Silk Road city near present-day Mary, and it is on the UNESCO World Heritage list. People lived on this spot from the 3rd millennium BC until the 18th century AD. It was among the greatest cities of Islamic civilisation, well known to Arab readers from classical books as Marw al-Shahijan. It passed through Achaemenid, Greek, Parthian and Sasanian hands, then to the Arabs, Ghaznavids and Seljuqs. In the early 9th century it was the seat of Caliph al-Ma'mun and capital of the whole caliphate, and in the 11th and 12th centuries it was capital of the Great Seljuks. Yaqut al-Hamawi counted ten great libraries here. In 1221 the Mongols caused massive destruction, and it never regained its standing. The cities here sit side by side and not on top of one another, so each age has its own walls. The oldest is Erk Kala, Gyaur Kala surrounds it, and beside it lies Seljuk Sultan Kala, the largest. Do not expect standing buildings everywhere, as you face a wide shrubby plain crossed by long worn earth walls, with the dome of Sultan Sanjar and the cone-shaped Great Icehouse rising from it. The site is about 33 km from Mary in a straight line, and the distances between its parts are long, so you need a car. The UK Foreign Office says tourists get an e-visa before travelling. Summer is very hot and shade is scarce, so choose spring or autumn, start in the morning and carry plenty of water.
Worn earth into the distance.
A cone of earth.
Rising from the plain.
Near Bayramaly, Mary Province, Turkmenistan
Half a day for the main parts by car, and a full day for the details.
One travel guide says it is required, and it helps a lot, as the site is vast with little explanation.