The entrance to Petra is a long, winding sandstone canyon known as the Siq (about 2km). There are minor carvings spotted here and there throughout the Siq, but the most impressive sights are the colorful and unusual sandstone patterns in the rock walls. There are also remains of terracotta pipes built into the sides of the canyon that were used in Roman times to carry water.
Upon exiting the Siq, visitors can view the jaw-dropping grandeur of theTreasury (al-Khazneh in Arabic). Be sure to note the urn atop the Treasury structure. It has been rumored that the urn contained a Pharaoh’s hidden treasure, and the urn bears the bullet pock marks where Bedouin travellers throughout the years have tested the theory. Get there when the park opens at 6AM or 6:30AM (depending on the season) and you may have the Treasury all to yourself or with less than 5-10 people around.
Outer Siq or Street of Facades
Past the next bend is the outer Siq or Street of Facades, a large canyon lined with the facades of various tombs.
At the end of the Street of Facades is the 7000-seat Roman Theater. The theater was created by the Nabateans but later enlarged by the Romans. It is still used for occasional performances.
On the side of the valley opposite the Roman Theater and a short walk up the hill, are the Royal Tombs. The name was given because they are quite grand in scale compared to the others in the area, but it is unclear for whom the tombs were originally constructed.Courtesy: Wikitravel