The Tuwaiq Hill Escarpment is approximately 600 m high. This escarpment crosses the Arabian peninsula from near the Yemeni border in the south 'Rub Al Khali' (The Empty Quarter) until the Al-Nafud desert in the North, around 1000 km. Escarpment forms a system of extensive canyons which cuts through the sandstone of Central Arabia.
Di batas kota Riyadh menuju Mekkah anda akan melewati dinding tegak setinggi 700 meter yang membentengi kota Riyadh disisi barat. Dinding ini (Bukit Tuwaig) membentang hampir sepanjang 1,000 km utara selatan ke arah padang pasir yg hampir tak terjamah "serambi kosong" atau Rab Al Kali yg hampir jarang sekali ada manusia melintas krn medan padang pasir yg sulit. Dinding Tuwaig yg terlihat digambar ada disekitar highway ke arah Mekkah yg dipangkas utk access utama masuk Kota Riyadh.
