What are the most worthwhile things to do in Petra on a first visit?

Petra is managed as a set of named routes, and reading that list before you arrive is the single most useful piece of preparation. Alongside the Main Trail, the authority prices and times fourteen further options. The Monastery main route is listed at 1.5 hours and 50 dinars. Al-Khubtha, which climbs from the Royal Palace tomb, runs 2 to 2.5 hours at 50 dinars. The shorter High Place of Sacrifices route, from the theater up and back, is 1.5 hours at 35 dinars, while the longer version continuing down to Qasr al-Bint is 3 hours at 60 dinars. Little Petra, reached through the Siq Albarid, is listed at 3 hours and 50 dinars.

Then there are the long days. The Monastery back route is given as 6 to 8 hours at 150 dinars. Aaron's Tomb and Wadi Sabra are both 8 hours at 150 dinars. Um Albiarah is 6 to 8 hours at 120 dinars. These are not variations on a stroll; they are full-day commitments on a site where the gate shuts at 16:00 outside summer, and the authority separates them into direct and indirect trails, with indirect routes quoted exclusive of the main trail cost. How many of those days you get is decided before arrival, at the national level: the Jordan Pass sells at 70, 75 and 80 Jordanian dinars, and the three tiers differ chiefly in Petra access — 1 day, 2 consecutive days or 3 consecutive days — with the tourist visa fee waived for pass holders who buy before arriving and stay a minimum of 2 nights.

What the trails deliver is the thing the inscription describes. Petra entered the World Heritage List under criteria (i), (iii) and (iv), recognized as an outstanding Nabataean achievement in rock-cut architecture and water engineering. The Treasury facade is the image; the tombs stacked along the Royal wall, the theater cut into the rock, and the dam and channel systems in the gorges are the evidence.

The Siq is the approach, a cleft about a mile long formed along a natural geological fault, with walls that rise in places well over 300 feet and narrow to a gap you can nearly touch both sides of before it opens without warning onto the Treasury.

The authority's list splits routes into direct and indirect, and the indirect ones are quoted on top of the main trail rather than instead of it. A visitor who buys a single day expecting to add the Monastery back route has, by the authority's own timings, committed six to eight hours on top of the two and a half the main route already takes — which is longer than the park is open on a non-summer day.

• Day one — The Main Trail end to end, 2.5 hours of walking before any stops, with the Royal tombs taken on the way back rather than on the way out.
• Day two, morning — One climb. Al-Khubtha at 2 to 2.5 hours gives the high view over the Treasury; the High Place of Sacrifices at 1.5 hours is the shorter alternative from the theater.
• Day two, afternoon — Little Petra through the Siq Albarid, 3 hours, which is a separate gorge with its own carved frontages.

Every long route is bounded by a gate that closes at 16:00, or 18:00 in summer, with site evacuation starting at sunset. The steep routes are stairs and scree rather than graded path, and the eight-hour trails are priced as guided undertakings at 150 dinars. Petra by Night occupies Sunday through Thursday evenings only, so an itinerary built around a weekend has fewer options than it appears to.

See the Petra food question in this group for where you can actually eat inside the park, and what the surrounding town offers after the gate shuts.