A ring of cliffs
Tuwaiq runs for about 800 km, from Nafud al-Thuwairat in al-Zulfi Governorate to the edge of the Empty Quarter, rising some 600 m above the surrounding plains. Its name comes from tawq, a ring, for the curved line of its peaks; it is also known as al-Arid and Arid al-Yamamah.
The range is limestone laid down since the Jurassic period, its coral heads a record of the sea that once covered the land. The highest point, Fareedat al-Shathiyah, northwest of al-Hariq, reaches 1,196 m, and Wadi Hanifah descends from its eastern face.
History and the Edge of the World
Caravans of pilgrims and traders crossed Tuwaiq on stone-paved roads, and in 1233 AH (1818) the Saudi army fought Ibrahim Pasha's Ottoman forces on its slopes during the invasion of Diriyah. Today it is the official icon of Qiddiya.
Its best-known rim, the Edge of the World, lies near al-Uyaynah about 100 km from Riyadh, overlooking an ancient trade route. Reaching it usually takes a four-wheel-drive vehicle and a climb of fifteen to thirty minutes, and it is most visited in autumn and winter.