Fodor's Expert Review Monastery (Ad Deir)

Although the Treasury may receive more visitors due to its proximity to the Siq, this remarkable structure carved into a mountaintop cliff is equally impressive—perhaps even more so. It takes 1½ to 2 hours to reach from the Visitor's Center by a winding 4 km (2 miles) trail with more than 800 steps at the end, so plan your time accordingly.

To reach it, trek the Main Trail through the Siq to the Treasury, passing the Roman Theater and Royal Tombs en route, then wind your way to the Basin through the Colonnaded Street. Just beyond the Basin, you'll climb the more than 800 steps to reach the Monastery (also known as Ad Deir). It may be less decorated than the Treasury, but at about 165 feet wide and 150 feet tall, it's larger, and there's much more space up here to spread out.

Cross etchings inside likely earned this monument its nickname. An inscription discovered nearby refers to "the symposium of Obodas, the God." From this inscription, archaeologists deduced that the Monastery was built around the 1st century BC as a meeting place for worshippers of Obodas. Either tomb or temple, it holds a spacious chamber cut deep into the mountainside, and offers sweeping views of the adjacent gorges.