Saw this lovely National Geographic article about Palmyra.
I visited Palmyra back in 2000 (alas, before my digital camera days, so no pictures!) It's a beautiful place, and very much in the middle of a desert. Like, sand-dune desert. Arid. Dry as a bone. Not a drop of water to be seen. Dry as a. . .well, you get the idea.
How did a town of 200,000 people survive in that environment? Extensive manipulation of rainwater and runoff water from nearby mountains. The article discusses new evidence for at least 35 farming villages around Palmyra, and extensive networks of reservoirs and canals.
A very interesting example of an agricultural landscape. I'll look forward to reading more.