Getting to Chaco Canyon is part of the point. The last stretch of road into this remote corner of north-western New Mexico is unpaved, rutted and washboarded, and after rain it turns to slick mud that can make it impassable for any kind of vehicle. Take that seriously: on a road bike it is tough, and on a big touring machine it can be miserable. But the reward is extraordinary. Between roughly 850 and 1150, the Ancestral Puebloan people built monumental great houses here, multi-storey stone buildings with hundreds of rooms, aligned with the sun, moon and cardinal directions, linked by straight roads across the desert. Chaco Culture National Historical Park was listed by UNESCO in 1987.
Pueblo Bonito is the most famous of the great houses, a D-shaped complex of around six hundred rooms and dozens of kivas, the round ceremonial chambers, built over several centuries. Walking through its doorways and courtyards, you see the precision of the masonry and wonder at the organisation needed to build it. On Fajada Butte, a spiral petroglyph marks solstices and equinoxes with daggers of sunlight, though access to it is restricted.
The park is also a certified dark sky park, with spectacular night skies and astronomy programmes. The landscape is high desert, with mesas, canyons and sagebrush, and the light at dawn and dusk turns the stone walls gold and red. Summer is hot, with afternoon thunderstorms, and winter can be cold, with snow.
Bloomfield and Farmington, to the north, have full services, and there are trading posts along the main highway. Carry plenty of water and food, and check road conditions with the park before setting out.
The riding to Chaco, apart from that last stretch, is about long open highways across the Navajo and Puebloan lands of the Four Corners, with vast views, little traffic and the occasional livestock on the road. April to early June and mid-September to October usually bring the kindest temperatures. Walk through Pueblo Bonito in the early morning, when the canyon is quiet and the shadows long, and feel the weight of a civilisation that built something this ambitious in such a hard land.