Seven Pillars of Wisdom by T.E. Lawrence

Leaving Hamra as dusk fell, we marched back down Wadi Safra until opposite Kharma, where we turned to the right up the side valley. It was closely grown with stiff brushwood, through which we drove our camels strenuously, having tucked up the streamers of our saddle-bags to save them from being shredded by the thorns. Two miles later we began to climb the narrow pass of Dhifran, which gave evidence even by night of labour expended on the road. It had been artificially smoothed, and the stones piled at each side into a heavy wall of protection against the rush of water in the rains. Parts had been graded, and were at times carried on a causeway built seemingly six or eight feet high, of great blocks of uncut stone: but it had been breached at every turn by torrents, and was in terrible ruin.

The ascent lasted perhaps for a mile; and the steep descent on the other side was about the same. Then we got to the level and found ourselves in a much broken country of ridges, with an intricate net of wadies whose main flow was apparently towards the south-west. The going was good for our camels. We rode for about seven miles in the dark, and came to a well, Bir el Murra, in a valley bed under a very low bluff, on whose head the square courses of a small fort of ashlar stood out against the starry sky. Conceivably both fort and causeway had been built by an Egyptian Mameluke for the passage of his pilgrim-caravan from Yenbo.