Petra was carved out of red sandstone in the 3rd century BC by the Nabateans.  The only entrance to the city is through a long, narrow gorge, known as the 'siq' which stretches for about 2km and sometimes no wider than a couple of metres.

 In the past, this gorge would have been packed with trading caravans, camels laden with finery and later on, the invading Romans, who, before conquering the city in 106 AD, would have had to fight their way down the entire passage.  

As you come out of the gorge, the first thing you will see is the Treasury, the statues and carvings adorning it ruined by Bedouin target practice.  The Bedouins would aim at the urn on top, believed to contain King Solomon's lost treasure. 

You can also still see the 7000-seat theatre, also carved entirely out of sandstone and a major stretch of Nabatean road which runs past an old market, which would once have been bustling with buyers and traders, but is now eerily deserted.

It is almost unimaginable that such an exquisite city could be hand-carved out of blocks of sandstone, mostly into the cliffs themselves, even more so when you see for yourself how huge Petra really is.  It takes at least a few days to explore fully, especially if you're considering exploring the outlying buildings, such as a beautiful monastery which sits on a hill just outside the city, or the High Place of Sacrifice; rain water collected up there would be used by the priests as holy water and you can stand at the altar where the blood once ran from the animals (and sometimes humans) who were sacrificed.

The city of Petra is absolutely fascinating and a must-see if you are interested in history. This website is an encyclopaedic guide to the whole city and Nabatean culture, which is a fascinating read if you can spare the time. 

Petra is a 2 hour drive from Amman and can be reached by bus or car.  There are a number of hotels to choose from in Petra and places inside that sell food and drink.  Passes and a guide are available from the nearby visitors centre.