The erg begins at the cliffs of the Tifoujar Pass, where the high ground of the Adrar plateau breaks apart, and pours southeast toward the mining town of Akjoujt. Beyond that it changes its name to Dkhaina and keeps going, stretching all the way to the Atlantic Ocean. What gives Erg Amatlich its peculiar character is its confinement. Hemmed in by mountains on either side, the sand cannot spread; it can only flow forward, channeled by the geology around it. The result is a dune barrier of almost architectural neatness - endless to walk through, yet narrow enough that from the heights you can often see rock on both sides. It is the Sahara distilled into a single bold stroke, the rest of the canvas left to mountain and plain.

To picture Erg Amatlich as nothing but sand is to miss it. Along its length the landscape keeps shifting register: canyons cut into the surrounding rock, sheer cliffs, and cultivable basins where the ground holds enough moisture to support life. On the western flank lies the palm grove of Azoueiga, a band of green that seems almost impossible against the surrounding dryness - proof that even in the heart of an erg, water finds a way to gather. These oases are not decoration. They are the reason people and caravans could cross this country at all, the islands of shade and dates that made the desert passable. The erg gathers, in a single corridor, nearly the whole vocabulary of Saharan landscape: dune and cliff, canyon and grove.

People have known this corridor for a very long time. Scattered through the region are Neolithic sites - among them Khatt Lemaiteg - left by communities who lived here when the Sahara was wetter and greener than the furnace it later became. Thousands of years ago, lakes stood where dunes now run, and the people who camped beside them left their traces in stone and worked tools. The desert that looks so empty is in fact a vast archive, its surface scattered with the evidence of a climate and a way of life long vanished. To cross Erg Amatlich today is to move through that record - past the palms of Azoueiga, between the cliffs of the Adrar, over ground that has been desert, savanna, and lakeshore in its turn, and may yet become something else again.