Commercial traffic to and from Petra increased steadily as caravans (sometimes with as many as a thousand camels) fed the demand for incense, textiles, spices, ivory and precious metals in Rome, Greece and Egypt. During this time the city evolved into a bustling hub of international commerce and culture. Located deep in the mountains, it was easily defensible from surrounding hostile desert raiders that might attack. "This place is exceedingly strong but unwalled…," wrote the Greek historian Diodorus when he visited it.
The Nabataean architects cleverly constructed a series of dams, cisterns and pipes to provide the city with much-needed water from a set of natural springs. As the wealth of the area grew, elaborately carved-public buildings were constructed along with gardens and monuments. Along the mountain walls that surrounded the city, impressive tombs were built for the richest families. At the height of its power around 50 AD, 20,000 residents dwelt in the city. A crossroads of trade also meant a crossroads of culture, so that architectural elements found in Petra's buildings showed influence from the Mesopotamian, Egyptian, Greek and Roman civilizations.
Petra has a reputation as a "lost city" but was never really missing to the Bedouin who lived in the area, though they did not refer to it by that name. Today one can visit the city, which is located in Jordan about 90 miles south of Amman, entering it through the same route Burckhardt took in 1812. Visitors walk through the narrow canyon, known as the Siq, to gain entrance to the ancient city. A stream once flowed through this narrow corridor, but the Nabataeans blocked the water with a dam and channeled it through a tunnel, a testament to their hydraulic engineering skills.
As the visitor approaches the end of the Siq, he beholds what is probably the most striking structure in Petra, the Khazneh. The name, which means "treasury," comes from a local legend that it hides riches. The story is told that Bedouins at one time believed that the giant urn on the second level of the facade was filled with treasures and they would fire their rifles at it, hoping to break it open. The facade of the building is carved into the rock face and stands over 120 feet high. The building is made even more impressive because of the high cliff walls surrounding the area in front of the building, making it difficult to look at the ancient towering structure from any distance. The way the fascade has been recessed into the cliff has protected the detailed ornamentation on it from much erosion, making the Khazneh one of Petra's best-preserved buildings.
Film buffs will recognize the Khazneh as the temple used in the final scenes of Indiana Jones and the Last Crusade. Though in the film the intrepid archeologist searches for the Holy Grail hidden deep inside the temple, the Khazneh and Petra have, in reality, no connection with that legend. The inside of the building is also quite unlike the extensive hollywood sets used in the film. The interior is simply a square room with two small connecting rooms and very little ornamentation. This is typical of most of Petra's tombs: ostentatious on the exterior, much plainer on the inside.