After turning off the West Ajo Highway, 20 miles west of Tucson, a car full of volunteers heads down a dirt track, carefully traversing the wide fractures in the road en route to plant the first cross of the day. The road is flanked on each side by rusted four-barred fences, behind which lie a couple of buildings with corrugated iron roofs.
The car is quiet, apart from the spade, bucket and cross rolling around in the trunk.
