The Siq (Arabic: السيق, transliterated al-Sīq, transcribed as-Sīq,[a] literally 'the Shaft') is the main entrance to the ancient Nabatean city of Petra in southern Jordan.
Also known as Siqit, it is a dim, narrow gorge (in some points no more than 3 metres (10 ft) wide) and winds its way approximately 1.2 kilometres (3⁄4 mi) and ends at Petra's most elaborate ruin, Al-Khazneh (the Treasury).
The arch collapsed in 1896 following an earthquake, but its appearance is known from the lithographs of Matthew Boulby and David Roberts.
Along both walls of the fissure are a number of votive niches containing baetyli, which suggest that the Siq was sacred to the Nabatean people.
Although the upper part is greatly eroded, it is still possible to recognise the figures of two merchants, each leading two camels.