Situated between the Red Sea and the Dead Sea and inhabited since prehistoric times, the rock-cut capital city of the Nabateans, became during Hellenistic and Roman times a major caravan centre for the incense of Arabia, the silks of China and the spices of India, a crossroads between Arabia, Egypt and Syria-Phoenicia. Petra is half-built, half-carved into the rock, and is surrounded by mountains riddled with passages and gorges.
The impressive eastern entrance leads steeply down through a dark, narrow gorge (in places only 3–4 m (9.8–13.1 ft) wide) called the Siq ("the shaft"), a natural geological feature formed from a deep split in the sandstone rocks and serving as a waterway flowing into Wadi Musa. At the end of the narrow gorge stands Petra's most elaborate ruin, Al Khazneh (popularly known as "the Treasury"), hewn into the sandstone cliff. While remaining in remarkably preserved condition, the face of the structure is marked by hundreds of bullet holes made by the local Bedouin tribes that hoped to dislodge riches that were once rumored to be hidden within it.
A little farther from the Treasury, at the foot of the mountain called en-Nejr, is a massive theatre, positioned so as to bring the greatest number of tombs within view. At the point where the valley opens out into the plain, the site of the city is revealed with striking effect.