Petra in jordan is on the BBC-list of the 20 places to see before you die.
This narrow gorge was the only way in to a society of 50.000 people 700 bc - notice the waterchannel cut out in the left side of the mountain. 
It was well placed on the spice and silk-route to Asia.
The Romans later conquered the city and was in charge untill an eartquake buried everything 700 ac. 
It was first discovered in 1810. 
"The treasury" is cut out of the montain. 
Only about 10 percent of the original city-area has been investigated.
