stone. Perhaps the best example of the Hellenistic style is seen in the Treasury, which is wide and tall and references the architecture of Alexandria. The facade of the Treasury features a broken pediment with a central tholos inside, and two obelisks appear to form into the rock at the top. Near the bottom of the Treasury are the twin Greek gods Castor and Pollux, who protect travellers on their journeys. Near the top of the Treasury, two victories are seen standing on each side of a female figure on the tholos. This female figure is believed to be the Isis-Tyche, Isis and Tyche being the Egyptian and Greek goddesses, respectively, of good fortune. Another prime example of Hellenistic architecture featured in Petra is its Monastery, which stands at tall and wide; this is Petra's largest monument and is similarly carved into the rock face. The facade of this again features a broken pediment, similar to the Treasury, as well as another central tholos. The Monastery displays more of a Nabataen touch while at the same time incorporating elements from Greek architecture. Its only source of light is its entrance standing at high. There is a large space outside of the Monastery, which is purposefully flattened for worship purposes. Formerly, in the Byzantine period, this was a place for Christian worship, but is now a holy site for pilgrims to visit. City centre At the end of the narrow gorge, the Siq, stands Petra's most elaborate ruin, popularly known as Al-Khazneh ("the Treasury"), hewn into the sandstone cliff. While remaining in remarkably preserved condition, the face of the structure is marked by hundreds of bullet holes made by the local Bedouin tribes that hoped to dislodge riches that were once rumoured to be hidden within it. A little farther from the Treasury, at the foot of the mountain called en-Nejr, is a massive theatre, positioned so as to bring the greatest number of tombs within view. At the point where the valley opens out into the plain, the site of the city is revealed with striking effect. The theatre was cut into the hillside and into several of the tombs during its construction. Rectangular gaps in the seating are still visible. Almost enclosing it on three sides are rose-coloured mountain walls, divided into groups by deep fissures and lined with knobs cut from the rock in the form of towers.