The Ad Deir (Monastery) is a colossal building carved out of rock in the ancient city of Petra, Jordan. Probably carved in the mid-1st century AD, it is one of the most iconic monuments within the Petra Archaeological Park. The monument sits high on a hill in the northwest of the city center of Petra. It is one of the most visited sites in Petra, second only to the Treasury (Khazneh) in popularity.