In Yemen's mountainous interior rain collects in thousands of cisterns built to follow the hollows in the land. Shaped by underlying rock, each is unique: large tanks water the terraced landscape, while small pools beside rural mosques hold the purest water for ablutions.

Walled off from its roadside or town setting, a rounded pool typically connects to a cubical mosque by stairs, the pool and the room for worship as tightly linked as a tea house is to its moss garden in Japan. In Yemen, both the pool and mosque (even its roof) are constructed of rough stone, waterproofed with polished plaster. These little mosques offer sanctuary in many ways. Acoustically, they are quiet; texturally, they are smooth; and visually, they are ordered by their white plaster covering. In every way they differ from the earth tones of the towns in which they are embedded, or the broken texture of the land along the roads they sit next to. Heavier than a tea house, less regular than Italian Trulli , they are nonetheless classically vernacular, with no exotic elements.

So far, these sites in Yemen's interior have escaped the fundamentalism which arose in Saudi Arabia. Craggy mountains, the tribes who fiercely defend them, and the Empty Quarter to the east have also kept out the more onerous forms of colonialism. Almost magically, they have even avoided the politics of nationalism. Any controversy, then, comes from within. However, in this regard, we find that no matter how calm the mosques look, they lie in a contested landscape. This is evident in the military checkpoints along roads, the defensive towers on every rocky pinnacle, and guard towers from which men protect their qat fields at night with rifles. Most males above the age of twelve wear a jambiya, and many also carry a Kalashnikov and a pistol. To allow trade in such tense circumstances, local people have been forced to designate certain areas as hijra, or sanctuaries, where they can congregate safely, and where they are honorbound to respect the peace.

Yemen has no plentiful natural resource but water - and that wealth is only relative to the rest of the Arabian Peninsula. And a recently doubled population, plus a focus on qat as a major cash crop, has led to anxious debate over water. At Kawkabam, a water war included one death. Most arguments revolve around water which outsiders "steal" by truck at night.

In such a tense landscape, where the resolution of revenge killings may take years, the tiny mosque with its ablution pool may offer an alternative. Tradition need not be invented; holy sites have been hijra from ancient times. But expanding the concept now to declare entire regions as hijra may well be a Yemeni invention that could offer hope of resolution. In any case, the inconspicuous mosque - the smallest, yet most perfect piece of the Yemeni water equation - may lie in the estimable position of safeguarding a sustainable supply of clean drinking water for the whole countryside.