The communal tombs (‘dolmens’) constructed through Europe and the Mediterranean region in the late Neolithic nearly always had an entrance to permit the introduction of further bodies, and hence an orientation. Extensive fieldwork shows that the builders always felt constrained to observe a custom of orientation, and in most of Western Europe the custom may well have been to face the rising Sun at some time of year, or the Sun after it had risen. But at Fontvieille near Arles the local custom was quite different, with tombs facing sunset or the Sun when descending. In southwest France and neighbouring parts of Cataluña the two customs are in conflict.