A 1.2 km gorge that drops 50 metres in height as it winds towards the Treasury. The walls rise sheer on either side, sometimes leaving only a metre or two of sky overhead, and the colour shifts from rose to deep red to black as the day moves. It was the ceremonial entrance to the city.
Look for the Nabataean water channels carved at shoulder height along both walls — the entire gorge was a managed aqueduct system, bringing winter rainwater into the city. Worn figures of caravan men and camels survive in low relief at the start, and small niches with carved baetyls — Nabataean god-blocks — appear at intervals. Walk it early; if you reach the Treasury before nine in the morning the light cuts straight down into the slot and the rock glows.