The most famous facade in Petra and probably the most famous rock-cut monument anywhere. Al-Khazneh stands 40 metres tall, carved into a single cliff face at the end of the Siq, and was probably the tomb of the Nabataean king Aretas IV in the early first century AD.
The architecture is consciously Hellenistic — Corinthian columns, a broken pediment, a circular tholos in the upper register flanked by half-pediments — executed not built. The whole facade was cut down from the top, with the rock removed in carefully calculated levels. Inside is a single, surprisingly plain rectangular chamber, with traces of a side niche where the sarcophagus probably stood. You cannot enter, but you can stand close enough to see the chisel marks.