Chaco is a place where you have to earn the silence. The way in is a long dirt road, many miles of corrugations and dust, that leaves the paved highway in the high desert of north-west New Mexico and runs across open range before dropping into a wide canyon, and by the time you arrive, you have been shaken and quiet for a good while. Then you see the walls. Between about the middle of the ninth century and the twelfth, the Ancestral Puebloan people built a dozen huge stone buildings here, called great houses, of which Pueblo Bonito is the largest, with hundreds of rooms in a D-shaped plan, stacked several storeys high, and a vast number of ceiling timbers carried in from forests far away.
Nobody is sure exactly what Chaco was, whether a ceremonial centre, a trading hub, a capital or all of those, but the builders clearly understood the sky. Many of the buildings are aligned to the solstices and the cycles of the moon, and on Fajada Butte, a slab of rock sits against the cliff in such a way that a spiral petroglyph was once crossed by daggers of sunlight at the solstices. Roads, perfectly straight and built across the landscape, link Chaco to outlying sites such as Kin Ya'a, and Halfway House, which belong to the same wider network. The park was listed as a World Heritage site in 1987.
The road is the challenge. The main access from the north, from the village of Nageezi on the highway, is about twenty miles of unpaved county road, rutted and washboarded, and after rain it can become impassable, so check conditions with the park before you set out. On a motorbike, a steady pace and some off-road skill are needed, and the dust can be thick, so carry a visor or goggles. Flash floods can fill the washes in summer, in the monsoon season of July and August, and the temperature swings widely, from hot afternoons to cold nights. The park is at about 6,200 feet.
A small campground is the only place to stay, and it fills quickly. The night sky here is among the darkest in the country, and the stars are spectacular. Walk quietly, stay on the paths, and leave everything as you found it.