The landscape is hot and barren. Horses kick up dust as their riders spur them on towards the gap in the rocks. With chequered headscarves drawn up over their faces to protect against the elements, they look like extras from Lawrence of Arabia, wild and energetic. A hump marks the beginning of the downward trail and suddenly you are in the Siq, a high, narrow fissure in the rock that runs for kilometres, becoming narrower and higher as it winds.

There is noise from the horses and people, but there is also beauty: strains of reds and purples running through the walls above and around you, the rays of the early morning sun occasionally breaking through to highlight the scene. You walk on, tiring, then suddenly there is a glimpse of something different ahead.

You turn the final corner to see the graceful lines of the Khazneh - the Treasury - carved out of the rockface dead ahead. In the morning sun the facade glows a subtle reddish brown. It is a stunning sight, and the first of many. This is Petra, the ancient carved city of the Nabateans, carved out of the mountains of southern Jordan.

Petra is a place that many have seen a picture of without being able to say for certain where it is. Though not as well-known as the Pyramids, it is one of the most impressive ancient sites in the Middle East and an increasingly popular attraction for Western tourists.

The Nabateans, the founders of Petra, were a tribe of pre-Islamic Arabs who built up an important trading empire in the lands between the coastal plains and the desert in what is now Jordan and southern Syria. Tolerated by the Roman Empire for some time as a buffer state between its territories and the desert tribes, Nabatea eventually became too big a rival and the Romans conquered it. The new overlords must have been impressed by their new possession, Petra, as it was no ordinary city.

The Nabateans carved virtually every building in Petra out of the rocky hills: tombs, halls, temples and meeting places, over a wide area and sometimes at improbable heights. Most of these buildings are intact and still present the visitor with a challenge. Climbing up mountain pathways in the Jordanian heat can be exhausting, but ultimately rewarding as you reach your goal.

There are ways around this exertion. The journey through the Siq can be done by horse or cart, and many buildings are at ground level or only slightly above. There is a shop, restaurant and a variety of cheap refreshment stalls in the area, as well as places selling souvenirs. For all this, it is easy enough to get away from the crowds and simply enjoy the sensation of the place.

If you want to see one of the high places, the easiest to reach is the Monastery, an hour's steady walk up the ancient stairs carved into the rock by the early inhabitants. It tires you if you're not fit, but the sight of the Monastery - very similar to the Treasury but much larger in scale - is breathtaking. No less so are the views of the terrain from the hillside behind the Monastery, sweeping across a rugged, parched landscape of rocky hills and wadis.

On a distant peak you can just make out a small structure, a shrine to Moses' brother Aaron (Haroun in Arabic). It was on the way to this shrine in the early 19th Century that a Swiss explorer rediscovered Petra, known in legend to the Western world but lost for centuries. The local Arabs were very secretive about its location, and many believed there was treasure concealed there. Proof of this can be seen in the facade of the Treasury, where a graceful urn is pock-marked with rifle shot. They needn't have bothered, as the urn is for decorative purposes only, carved from solid rock.

There are modern resonances in Petra as well. Indiana Jones and the Last Crusade, the last in the movie trilogy, was partly shot in Petra with Harrison Ford rushing into the Treasury near the end of the film to face the ultimate test. Tourists seeking to follow in his footsteps will be disappointed as the interior of the Khazneh is just a big, empty, unadorned room. Though the Nabateans were experts at exterior design in stone, they relied on more fragile materials for decoration within. Some of these everyday items are preserved in a small museum, itself located inside an old chamber carved from the rock.

Petra is also in Lawrence of Arabia country, not far from Aqaba, Wadi Rum and other locations where Lawrence and his Arab warriors fought. It is an area still largely undeveloped and it does not take much to fire the imagination and imagine its colourful past.

With tourists seeking alternatives to the traditional Middle Eastern destinations of Egypt and Turkey, tourism to Jordan is increasing and Petra is feeling the pressure of numbers. New hotels are being built near Petra and the neighbouring town of Wadi Musa, and day trips run from the cities of Amman and Aqaba. The authorities are working on ways to minimise the environmental impact of increased tourism while keeping the site accessible.

For all the hordes of people visiting the ancient city, however, Petra is one of the most stunning sites of the Middle East and should be on the itinerary of all visiting the region. With access now possible through Israel as well as the traditional entry points of Amman and Aqaba (by ferry from Egypt), it is easier to see now than at any time in the past.