When UNESCO listed the Historic City of Yazd in 2017 it described a living desert town of earthen architecture, and the zones in the description, such as Area 1, divide the old city into parts for protection. The mosque, begun in the twelfth century and added to over the next three, has one of the highest entrance portals in Iran, and the dome inside is a cool, blue-tiled cavern.
From the rooftops you can see how the old city is built, with a continuous skyline of domes, flat roofs and wind towers, and behind them the pale ridge of the Shirkuh mountains. Yazd was a stop on the caravan road between Isfahan and Kerman, and merchants brought silk, cotton and carpets through its gates. Marco Polo visited in the thirteenth century and called it a good and noble city, which still sounds right. The city is also a centre of the Zoroastrian faith, with a fire temple whose flame is said to have burned for more than fifteen centuries, and the dry hills outside the city still hold the Towers of Silence, where the dead were once left to the vultures.
Practicalities are simple. Use the edge of the old town for parking, since the lanes are narrow, and walk. Early morning is the quietest time, and the sun in the lanes is low and soft. The bazaar is covered, cool and full of copper pots, textiles and sweets, and you can bargain in a friendly way. Tea houses on the roofs serve tea and kalian, the water pipe, with a view across the domes, and sunset there is memorable, as the call to prayer drifts out.
Fuel is available along the ring road, and the city is large enough for every service, including spares and mechanics. In summer it is very hot, so plan sightseeing before ten in the morning and after five in the evening. Dress modestly, with long sleeves and trousers, and women should carry a scarf. Take plenty of water, and if you have energy left, ride out to Meybod, a small town with an old citadel and a pigeon tower, about an hour north-west.