Since Jordan made peace with Israel in 1994, the trickle of visitors has grown to a stampede, from 700 a day to 4,000: Israelis by the busload, but more often foreigners taking in both flanks of the Holy Land. The government has given up trying to limit the daily influx of tourists.
When I was last here, two years ago, the neighbouring bedouin township of Wadi Mussa (population 22,000) boasted three hotels. Now it has 32, four- and five-star and still building, not to mention "Petra Burger" joints and T-shirt shops offering 25 per cent discounts in Hebrew. Land values have soared from about pounds 2,000 an acre to pounds 200,000. The town's 3,500 houses are being painted Petra-pink by order of Queen Noor.
"In the summer," said a local guide, Mahmoud, a bedouin with a masters degree in electrical engineering, "the people here used to take their goats and tents into the hills and become nomads again. This year they're all working in tourism."
Dean Burgon, an obscure 19th-century Anglican, hymned Petra as "a rose- red city half as old as time". More prosaically, Mahmoud counts 15 different coloured stripes, traces of untapped minerals, in the sandstone caves and cliffs. Edward Lear's travelling cook described it as a place "where everything is chocolate, ham, curry powder and salmon". A British archaeologist, Crystal Bennet, chided him for leaving out the vanilla ice cream and blueberries.
You can travel to the site quite simply - by bus or hired car from Amman (125 miles down the Desert Highway) or Aqaba (75 miles). There are also day trips from Aqaba's twin Israeli Red Sea resort of Eilat. Yet Petra itself remains a challenge.
Vehicles are banned. From the government tourism centre, you ride a horse, walk or take a buggy through a dark, dry, narrowing ravine that rears to 200ft on either side, then opens with a shock of revelation on the sun-drenched pink facade of the "Treasury", 135ft high by 75ft wide, with its exquisitely carved pillars and pediments, domes, decapitated gods and eagles. "This is the way every city should greet its visitors," marvelled an architect member of our party.
To the west, the Treasury plaza broadens into a stone-strewn valley with more temples cut in the walls on either side - all facades, with square, rainbow-striped caves hollowed out behind them. The Nabatean merchants built to impress, but lived more modestly.
The Romans, who followed them, added an amphitheatre and a paved and pillared road, the Byzantines a monastery. King Hussein's contribution, a scatter of coffee shops and at least one public lavatory - housed inside a cave with water mysteriously on tap - manages not to intrude.
Petra is built on scale which absorbs the multitude of visitors exploring on foot in the desiccating heat. From the Nabatean "High Place", 900 steps up the mountainside, their figures appear tiny, Lilliputian. Two thousand years after it was hewn from the cliff-face, Petra still dwarfs the modern world.