While you can explore the vast archaeological city of Petra, you cannot go inside the famous "Treasury" (Al-Khazneh). For conservation reasons, the Jordanian authorities prohibited entry to the interior of the Treasury years ago to prevent damage from the thousands of daily tourists. Furthermore, the interior is relatively underwhelming; it is a simple, dark, and empty chamber with no murals or furniture. However, you can go inside other major monuments, most notably the Monastery (Ad Deir), which features a large, carved interior chamber. You can also enter the Royal Tombs and several smaller cave dwellings throughout the site. In 2026, the best way to "see" inside the Treasury is to look through the open doorway from the exterior or to view historical photographs taken before the ban. The true wonder of the Treasury is its spectacular, 40-meter-high Greco-Roman-style facade carved directly into the rose-red sandstone cliff, which remains perfectly accessible to all visitors at the end of the Siq.