Petra means "rock" in Greek. A very appropriate name.  
The trail leads to this famous art shot showing a portion of
Petra's most famous building, known as the Treasury.
The Treasury was carved out of sandstone about 2,000 years
ago by the Nabataean civilization, which developed Petra as a
center for caravan commerce.  The Treasury exterior
appeared in the film "Indiana Jones and the Last Crusade"
as the climax setting.  35,000 people may have lived in Petra
at the height of its glory, using caves carved from the rocks.    
The interior is empty now, but the Treasury must have been
intended to impress every visitor to Petra.  The Romans were
impressed enough to conquer Petra as part of their empire.  
My best Treasury photo is back at the first page, click
Here .
The Obelisk Tomb is another of Petra's famous
structures, all carved out of sandstone.
If you have a high speed internet connection, watch the
Intrepid Berkeley Explorer's free video of this trip by
clicking on:
Land of Milk and Chutzpah