The Richat Structure

From orbit, the Sahara stares back: the Richat Structure - Guelb er Richat - draws concentric rock rings some forty kilometres across, a bullseye so conspicuous that astronauts used it as a landmark from the first missions. Geology's verdict is an eroded dome, not the crater it resembles: layered rings of resistant rock left standing as the softer strata wore away, with the debate over details still employing researchers. On the ground the scale dissolves into a landscape - ridges, gaps and gravel plains the 4x4 pistes thread from Ouadane - and the pleasure is the surreal knowledge of driving across the pupil of the desert's eye, camping where the rings rise like frozen surf.

What you actually see

• The ring ridges - concentric rock waves crossed by the pistes.
• The central dome - the eye's core and its mineral colours.
• The rim viewpoints - the structure's curve read from high ground.
• The desert camps - nights inside the bullseye.

When to go

November to February for workable temperatures; the structure reads best in low morning and evening light when the ridges shadow. It folds into the Ouadane day or an overnight camp.

Honest expectations

At ground level the 'eye' is landscape, not spectacle - visitors expecting to see the rings whole need satellite imagery or a drone; the wonder is contextual, and a guide who narrates the geology earns the fee. Standard deep-desert rules: convoy or experienced driver, water margins, no improvising.

Nearby

Ouadane's ksar, the Adrar pistes and Atar.