ARCOS DE LA FRONTERA.View over Guadalete River to clifftop town of Arcos de la Frontera . One of Andalucia`s most dramatically positioned pueblos blancos white villages, Arcos balances atop a rocky limestone ridge, its whitewashed houses and stone castle walls stopping abruptly as a sheer cliff face plunges down to the fertile valley of the river Guadalete below.The pueblos blancos white towns