Petra was the capital of the Nabataean Arab kingdom from around the 4th century BCE and a major hub on caravan routes linking Arabia, Egypt, and the Mediterranean. The city is partly built and partly carved directly into the rock, creating a unique cultural landscape that has been described by UNESCO as one of the most precious elements of human heritage.
 
Petra lies in southwest Jordan, in the Ma’an Governorate, on a rocky terrace cut by the Wadi Musa between the Dead Sea and the Red Sea. Access is through the Siq, a narrow, roughly 1.2 km-long gorge whose high cliffs dramatically reveal the first major monument, the Treasury, at its end.
 
Al-Khazneh seen above  (“The Treasury”) is Petra’s most iconic façade, about 45 m high, probably a royal tomb from the reign of King Aretas IV, and famously featured in “Indiana Jones and the Last Crusade.”
 
Interesting facts....
Still in discovery. Satellite imagery and aerial photography have revealed previously undocumented buildings and features a little over a mile southwest of the main city, including large platforms and building remains whose function is still uncertain. Ground‑penetrating surveys and excavation have revealed a previously unknown tomb complex directly beneath the Treasury (Al‑Khazneh), with a chamber containing 12 skeletons still in situ.