Al-Dayr : one of the largest monuments in Petra,measuring 47 m. wide by 48,3 m. high. It was built on the model of the Khazna but here the bas-reliefs are replaced by niches to house sculptures. A column portico extends in front of the facade.The interior is ocupied by two sides benches and an altar against the rear wall.It was used as a biclinium for the meetings of the religious associations and dates to the early 2nd.Century AD during the reign of King Rabel II. In the Byzantine period the hall was reused as a Christian Chapel and crosses were carved in the rear wall thus the name "Monastery"(Dayr in Arabic).