Petra belongs on the top of any Jordan itinerary. The Nabataeans carved an entire city out of the red sandstone of the Wadi Musa canyon — temples, tombs, dining halls and processional ways, all out of the living rock — and they did it so well that the place still works as architecture two thousand years later.
The visit starts on foot through the Siq, a narrow gorge a kilometre and a half long whose walls rise more than 150 metres above your head. The gorge bends, twists, and finally narrows to a slot. Then it opens. What stands in front of you is Al-Khazneh — the Treasury — a 40-metre-high facade so improbably perfect that the moment of arrival has become one of the most photographed in the world. Photographs do not prepare you for it; the scale only registers when you are standing under it.
After the Treasury the canyon opens into a wider valley. Hundreds of tombs are cut into the cliffs, a Roman theatre carved straight from the rock seats 8,000 people, and a paved colonnaded street runs past the Nabataean public buildings — the Great Temple, the Temple of the Winged Lions, and the Qasr al-Bint. To see the full extent you need a day, ideally two: the Monastery (Ed-Deir) is an 800-step climb beyond the main basin, and the High Place of Sacrifice sits on the ridge above, both rewarding the effort.
Petra is hot and exposed. Bring more water than you think you need, wear real shoes, and start early — by ten o'clock the Treasury area is crowded and the rock has warmed enough to bleach the photographs. The base for visits is the small town of Wadi Musa directly above the site, where you will sleep and eat.
Petra sits less than 200 km south of Amman. You can do it as a long day trip on the Desert Highway, but you will miss half of it. Combine it with Wadi Rum to the south, and Little Petra and Beidha on the way north for the fuller picture.