Some main archeological sites inside the city are the Treasury – the tomb of a Nabatean king, the Monastery – an isolated mountain temple, a theatre, government buildings and dwelling for regular people.

While the exterior "Treasury" (Al-Khazneh) of Petra is world-famous for its intricate facade, the interior is surprisingly plain and empty. If you were to step inside the Treasury, you would find yourself in a large, square, unadorned chamber carved directly into the sandstone, with three smaller antechambers. There are no carvings, statues, or hidden treasures inside; the Nabataeans focused their artistic efforts almost exclusively on the exteriors to serve as monumental markers for what were essentially royal tombs or mausoleums. However, "inside" the wider Petra Archaeological Park, there is an immense city. This includes a massive Roman-style theater that could seat 8,500 people, the "Colonnaded Street," a Great Temple, and the "Monastery" (Ad Deir), which is even larger than the Treasury. Recent excavations have also uncovered hidden tombs underneath the Treasury's floor. So, while the most famous building is empty, the "city" of Petra contains thousands of structures, tombs, and ancient water systems that are still being explored today.