Petra is an ancient city carved into rose-coloured sandstone cliffs in southern Jordan, about 240 kilometres south of Amman. Built by the Nabataeans from roughly the 4th century BCE, it grew rich controlling the caravan trade in frankincense and myrrh. It became a UNESCO World Heritage Site in 1985 and one of the New Seven Wonders of the World in 2007, and only a fraction of its estimated extent has been excavated.
The Nabataeans and the Incense Road
The Nabataeans were originally a nomadic Arab people who, by around the 4th century BCE, had settled the arid uplands of what is now southern Jordan. Their wealth came not from agriculture but from position: they controlled the northern reaches of the incense route carrying frankincense and myrrh from southern Arabia — modern Yemen and Oman — toward the Mediterranean ports, along with spices from India and bitumen from the Dead Sea.
Petra sat at the junction where those routes converged before turning toward Gaza. The Nabataeans levied tolls, provided water and protection, and reinvested the proceeds in the city. At its height, probably in the 1st century CE, Petra may have held on the order of 20,000 to 30,000 people.
Their advantage was partly military. The historian Diodorus Siculus records that the Nabataeans repelled a Greek expedition under Antigonus I around 312 BCE, in part by concealing water in cisterns that only they could find — the earliest surviving written account of the people, and one that already identifies water as the basis of their power.
Nabataean is written in an Aramaic-derived script that is a direct ancestor of the modern Arabic alphabet, making Petra's inscriptions a significant waypoint in the history of writing.
Walking the Siq
The approach to Petra is deliberate theatre. The main entrance runs through the Siq, a natural gorge roughly 1.2 kilometres long, formed not by water erosion but by tectonic forces splitting the rock mass apart, then smoothed by flash floods. In places it narrows to about three metres while the walls rise as high as 180 metres.
The Nabataeans engineered it heavily. The floor was paved, and ceramic pipes and rock-cut channels ran along both walls carrying water into the city. Niches cut into the rock held betyls — abstract standing-stone representations of Nabataean deities such as Dushara — so the passage functioned as a processional way as much as a road.
The gorge ends abruptly with a narrow vertical slot through which Al-Khazneh appears. The effect is entirely intentional, and it is the reason Petra reads as a designed experience rather than a collection of monuments.
Al-Khazneh Is a Tomb, Not a Treasury
Al-Khazneh means "the Treasury", but the name is a misnomer that dates only to the modern era. Local Bedouin tradition held that the stone urn on the upper level concealed a pharaoh's treasure, and it is pocked with bullet marks from attempts to break it open; the urn is solid sandstone.
The facade stands roughly 40 metres tall and about 25 metres wide, and is almost certainly a royal tomb, most commonly attributed to King Aretas IV, who ruled from about 9 BCE to 40 CE. Its architecture is strikingly Hellenistic — Corinthian capitals, a broken pediment, a central tholos — showing how thoroughly the Nabataeans absorbed Mediterranean design while remaining independent.
The critical technical point is that it is not built but subtracted. The facade was carved directly into the cliff, top down, so masons worked from scaffolding at the summit and cut downward, removing the working platform as they descended. There is no possibility of correcting an error, which makes the precision of the surviving surfaces remarkable. The chambers behind are plain and comparatively small — the entire investment went into the exterior.
Ad-Deir, "the Monastery", is larger still at roughly 45 metres wide and 48 metres tall, reached by a rock-cut stairway of some 800 steps. It is less visited simply because of the climb.
The colour that gives Petra its reputation is a product of geology rather than weathering. The rock is Cambrian and Ordovician sandstone stained by iron and manganese oxides in irregular bands, so cut surfaces reveal swirling reds, pinks, ochres and greys that shift markedly with the angle of the sun. Interiors carved into the same stone — particularly the so-called Silk Tomb — show the banding far more vividly than the sun-bleached exteriors do.
The Water Engineering Beneath the Rose Rock
Petra receives on the order of 150 millimetres of rain a year, almost all of it in short winter downpours. Supporting a city of tens of thousands in that setting was a hydrological achievement, and it is arguably the Nabataeans' real monument.
The system combined several techniques. Dams and diversion tunnels — including a substantial tunnel at Al-Muthlim — redirected flash floods away from the Siq, which would otherwise have scoured the processional route and drowned anyone in it. Ceramic pipe networks, laid at carefully calculated gradients to control flow velocity and prevent the pipes bursting, carried spring water into the city from sources several kilometres away, including Ain Musa. Hundreds of rock-cut cisterns stored the winter surplus, many with sedimentation basins upstream to settle out silt, and many concealed.
The scale of the achievement is easiest to grasp through failure: in 1963 a flash flood swept through the Siq and killed more than twenty visitors, because the ancient diversion works had silted up and fallen out of use. They have since been restored. Jordan's wider aridity and water constraints are covered in our Jordan geography guide.
Rome Annexes Nabataea, and Petra Fades
In 106 CE the Emperor Trajan annexed the Nabataean kingdom, which became the Roman province of Arabia Petraea. The takeover appears to have been peaceful; there is no record of a war of conquest.
Roman Petra was not immediately diminished. A colonnaded street was laid out, a theatre cut into the rock was enlarged to seat several thousand, and the city retained importance. But the trade that had made it wealthy was already shifting. Improved understanding of the monsoon winds made maritime routes through the Red Sea faster and cheaper than overland caravans, and Roman administration favoured Bosra to the north, which became the provincial capital.
A severe earthquake in 363 CE destroyed a large part of the city and damaged the water system beyond economical repair. Petra continued as a Byzantine bishopric — a 5th-century church with substantial mosaics has been excavated, along with a cache of carbonised papyrus scrolls — but a further earthquake in 551 and the subsequent shift of regional power effectively ended urban life. By the time of the Crusades, when a small castle was built nearby, the city was a memory.
Rediscovery in 1812 and the Modern Park
Petra was never lost to the local Bedouin, particularly the Bdoul, who lived among the monuments and used the caves as dwellings. It was lost to Europe. In 1812 the Swiss traveller Johann Ludwig Burckhardt, travelling in Arab dress and under the name Sheikh Ibrahim, persuaded a guide to take him to the site on the pretext of making a sacrifice at the tomb of Aaron on nearby Jebel Haroun, and became the first European in centuries to see it.
The phrase "a rose-red city half as old as time" comes from John William Burgon's 1845 prize poem Petra — written, notably, by a man who had never been there.
The modern site is large: the archaeological park covers over 260 square kilometres, and surveys using remote sensing have identified substantial unexcavated structures, including a large platform near the city centre found via satellite imagery in 2016. Estimates commonly cited suggest only a small percentage of Petra has been excavated. In the 1980s the Bdoul were relocated to the purpose-built village of Umm Sayhoun, a resettlement that remains contested locally.
Petra Measured Against Its Sister City, Hegra
The most direct comparison is not with Rome or Egypt but with Hegra — Mada'in Salih — in north-western Saudi Arabia, the Nabataeans' second city and their southern trading hub. Hegra became Saudi Arabia's first UNESCO World Heritage Site in 2008.
The two make an unusually clean contrast because the same civilisation built both. Hegra has over 100 monumental rock-cut tombs with decorated facades, many carrying inscriptions that name the tomb owner, the sculptor and the date — documentation almost entirely absent at Petra, which is why Hegra is in some respects the more informative site for scholars.
What Hegra lacks is Petra's urban fabric and its topography. Hegra's tombs are cut into free-standing sandstone outcrops rising from open desert, scattered rather than concentrated, with no equivalent of the Siq, no theatre and no colonnaded street. Petra is a city; Hegra is principally a necropolis and caravan station. Hegra also receives a tiny fraction of the visitors, having been closed to general tourism until 2020.
For the wider region, see our guides to the Wadi Rum desert and the Dead Sea, both within a few hours of Petra, or test your knowledge of the world's great monuments in our landmark quiz.
