The Kuiseb River is the line that holds back the dunes. Flowing only after rare rains, it winds across the gravel plains of western Namibia toward Walvis Bay, and for most of its length it forms a natural barrier, with the great sand sea of the Namib to the south and the stony desert to the north. Where the road crosses it, in the Kuiseb canyon, the land drops into a gorge of dark rock, with dry riverbed, acacia and ana trees far below the plain, and the pass is a short, steep ride down and up the other side.
The canyon has a remarkable story. During the Second World War, two German geologists, Henno Martin and Hermann Korn, hid in this region for over two years to avoid internment, living off game and what they could find, and Martin later wrote a book about it, published in English as The Sheltered Desert. Their story is a reminder of how harsh and beautiful the place is. The Topnaar people, who have lived along the river for generations, harvest the !nara melon, a spiny plant that grows in the dunes and provides food and income.
Riding here means gravel and a lot of space. The road is usually in decent condition, but loose stones, washboard and sand drifts can catch you out, and the gradients into the canyon are steep enough to need care. Wind often blows hard in the afternoon, throwing dust across the road, and in the middle of summer the heat is intense. Watch for oryx and springbok that wander across the track, and give lorries plenty of space, as they raise clouds of dust.
Services are almost non-existent along this stretch. Solitaire, to the south-east, and Walvis Bay, on the coast, are the places for fuel and supplies, and it is sensible to carry extra fuel and plenty of water. If you stop in the canyon, be aware that flash floods are possible after rain in the distant highlands, even if the sky above you is clear, so do not camp in the riverbed. A pause on the rim, with the silence and the heat shimmering off the rocks, is a good reminder of the scale of this desert.