The eastern edge of the Grand Erg Oriental begins about 30 km east of Touggourt and stretches almost unbroken to the Tunisian border and beyond. The dunes are some of the highest in the Sahara, and the silence between them is absolute. The road to El Oued crosses the very northern fringe and gives a good sense of the scale.
For a closer look, hire a four-wheel-drive and guide in Touggourt or, better, in El Oued itself. Sunrise and sunset on the dunes are the obvious moments, but the colour and light shift continuously through the day. Travel here requires permits and ideally an organised tour.