English: The Siq is a 1.6 km long narrow gorge that leads into the city of Petra, emerging dramatically in front of the Treasury. The entrance to the Siq was originally marked by an ornamental arch; it collapsed in 1896, but its decorated abutments survive.

The Siq is not technically a gorge, as it was formed not by erosion but tectonic forces, which caused the the rock to split dramatically in half. It was only then that the waters of the Wadi Musa flowed in and the winds blew through the newly-formed gap, gradually rounding the sharp edges into smooth curves. Today, the Siq is a meandering path between beautifully-colored sandstone cliffs about 200m high on each side. Occasionally the path widens enough to allow in warm sunlight and even a tree; other times it becomes so narrow (as little as 2 meters apart) that the stone seems to block out virtually all heat, light, and sound.

Along the way are some small niches, shrines and carvings to investigate, and running alongside the length of the Siq are water channels carved by the Nabateans to provide water to the city of Petra. Anticipation builds as the walk goes on, and the end of the Siq is a dramatic moment - planned that way by the Nabateans to impress their visitors. The gorge narrows, and the soft curves of the Siq frame a sunlit strip of an extraordinary sight: the Treasury.