Here in the desert, in the south of Israel, it seems like you can't move a mile without hitting some ancient Nabatean ruin. The Negev is pockmarked with cisterns that still function during the rains, and occasionally you can see caves hidden away in the wadi walls. I've visited almost every Nabatean settlement in the Negev, thanks to a course i took with the desert school called "Desert Settlements through time and space". The really interesting things about the Nabateans were their agricultural system which consisted mainly of runoff farming and their ability to build houses out of stone. And also the mystery of the lime covering in the cisterns and tanks. Lime need to be heated to an extraordinary degree in order to function as a waterproofing agent and in the negev, there is just not enough wood to provide the heat. The jury is still out on this issue, but i personally think that there was a lot more vegetation in those times.
ok. i have to confess. i wrote all of the above just because i stumbled onto a great link to Petra, the Crown City of the Nabateans(needs QuickTime Plugin), in Jordan. Sadly, its other claim to fame nowadays is the fact that Petra formed the setting for the movie 'Indiana Jones and the Last Crusade'. But it is nevertheless an archetypal lost city. More about the Nabateans can be found here and this site talks about their presence in israel.