The main road, from the point where the branch to St Césaire leaves it, continues westwards and descends with many wide and bold sweeps till it reaches the Siagne, which it crosses at Les Veyans, and again ascends the steep and wooded valley on the opposite side. Soon the rugged ruins of the castle of Tournon (Fig. 198) are seen frowning over the pass from their rocky eminence, which can only be reached after a hard climb through the thick wood and thorny heath which clothe the hillside. But that trouble is rewarded by the discovery of a rude and remarkable edifice. This consists of a Keep of semi-circular form built on the edge of a precipice which forms the diameter of the circle, and has apparently been considered a sufficient defence of the structure on that side. A semi-circular lofty wall of enceinte surrounds the keep on the side next the hill. The entrance gateway was doubtless in this wall where there is now a ruinous gap. The building is reduced to bare and shattered walls, so that its interior arrangements cannot be determined, but it must have been a very singular and unique structure. [Illustration: FIG. 199. TOWN AND CASTLE OF CALLIAN.] Near the highest point of the road, in continuing westwards, the village of La Colle-Noire stands across the way, and in olden times stopped all passage by means of gates in its walls. Beyond this, an open country rich in vines and olives is traversed, from which another long ascent leads to the town of Montauroux, standing on a promontory, crowned with the ruins of the Fort St Barthélemy, destroyed in 1592. A wide curve of the road, round a fine amphitheatre of terraced lands, leads from Montauroux to Callian, another little town perched on the hillside, and commanded by the immense ruins of an old castle (Fig. 199), which like all the others in the province, was sacked in 1792, and of which only the shattered shell remains. It would appear from the mullioned windows and round tower, to have been built in the fifteenth century, and has evidently been altered in the seventeenth, by the insertion of numerous large oblong openings. In the sixteenth century this pile was inhabited by Jean de Grasse. [Illustration: FIG. 200. LE BAR, S. DOORWAY OF CHURCH.]