Petra ("petra-p?t?a", cleft in the rock in Greek; Arabic: ???????, Al-Batra?) is an archaeological site in the Arabah, Ma'an Governorate, Jordan, lying on the slope of Mount Hor in a basin among the mountains which form the eastern flank of Arabah (Wadi Araba), the large valley running from the Dead Sea to the Gulf of Aqaba.
It is renowned for its rock-cut architecture. Petra is also one of the new wonders of the world. The Nabateans constructed it as their capital city around 100 BC.
The site remained unknown to the Western world until 1812, when it was introduced to the West by Swiss explorer Johann Ludwig Burckhardt. It was famously described as "a rose-red city half as old as time" in a Newdigate prize-winning sonnet by John William Burgon. UNESCO has described it as "one of the most precious cultural properties of man's cultural heritage."[3] In 1985, Petra was designated a World Heritage Site.
Pliny the Elder and other writers identify Petra as the capital of the Nabataeans, Aramaic-speaking Semites, and the centre of their caravan trade. Enclosed by towering rocks and watered by a perennial stream, Petra not only possessed the advantages of a fortress, but controlled the main commercial routes which passed through it to Gaza in the west, to Bosra and Damascus in the north, to Aqaba and Leuce Come on the Red Sea, and across the desert to the Persian Gulf.
Excavations have demonstrated that it was the ability of the Nabataeans to control the water supply that led to the rise of the desert city, in effect creating an artificial oasis. The area is visited by flash floods and archaeological evidence demonstrates the Nabataeans controlled these floods by the use of dams, cisterns and water conduits. These innovations stored water for prolonged periods of drought, and enabled the petra city to prosper from its sale
Although in ancient times Petra might have been approached from the south via Saudi Arabia on a track leading around Jabal Haroun ("Aaron's Mountain"), across the plain of Petra, or possibly from the high plateau to the north, most modern visitors approach the ancient site from the east. The impressive eastern entrance leads steeply down through a dark, narrow gorge (in places only 3�4 metres 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.