Xi'an's city wall is the reason the old city still reads as a city rather than a collection of sights. It is a complete rectangle - roughly fourteen kilometres around, twelve metres high and wide enough at the top for two cars to pass - and it survives because it was never comprehensively demolished. It is possible to hire a bicycle and go round in an hour and a half. It is also possible, and much better, to walk it, which no more than a handful of visitors do on any given day.
The wall and how it works
The present wall is Ming, begun in the 1370s on the line of the Tang imperial city wall, and it follows the standard grammar of Chinese fortification: an outer brick face over a rammed earth core, crenellations on the outside only, a walkway on top, and a moat outside that. There are four great gates, one at each side, each with an outer barbican - a walled enclosure in front of the gate with its own opening set at right angles, so that attackers who broke through were trapped. The south gate, Yongningmen, is the grandest and the one most people start from; the west and east gates are quieter and give a better sense of how the fortifications worked.
Walking the circuit
At a normal pace the full loop takes three to four hours, including stops. The surface is flat and even, with a shallow camber in places and steps at the gate towers; there is almost no shade, and the wind on top is constant. Walking anticlockwise from Yongningmen puts the wall towers on your right. Take water, and expect to be stopped regularly by people asking for photographs. The best sections are the corners, where the wall turns and the guard towers cluster, and the stretch along the western side, where you look down into the old residential lanes.
Practical notes
There is one admission ticket for the wall, valid at all gates, plus a separate charge for bicycle hire if you choose to ride. The wall is open from morning until late evening, and the gates are lit at night. It is pleasant at any time of day, but the two hours after opening and the hour before sunset are the best light and the coolest conditions. Combine the walk with the lanes inside the wall rather than the tourist streets outside it, since the residential quarters immediately south of the wall have the best-preserved courtyard houses in the city.
