- "Petra is a brilliant display of man's artistry in turning barren rock into majestic wonder."
– Edward Dawson
Petra can turn a desert city into a bustling metropolis with high growth and Production potential. However, the city can quickly run into Housing issues, since it receives a huge amount of Food but very few improvements can be built in deserts to provide extra Housing. For this reason, Petra is best built in a city with a lot of Desert Hills, which can be further improved with Mines. Running domestic Trade Routes from the city or using Isidore of Miletus or Filippo Brunelleschi (or a few Builders' build charges, when playing as Qin Shi Huang) can provide the Production needed to complete Petra quickly.
Civilizations like Australia, Nubia, China, India and Mali, which can improve flat Desert tiles or have Housing bonuses independent from standard improvements, are able to gain extra utility from Petra. They should always focus on having a productive desert city if they manage to build it.
Gathering Storm makes deserts much more desirable thanks to dust storms, which can significantly improve the base yields of Desert tiles. Of course, this won't change the situation with improvements, but it adds one more source of growth and Production that desert cities always need. Additionally, the Nazca Line, which is available if you're the Suzerain of Nazca, can help you further improve Desert tiles in Petra's city. Bear in mind, however, that tiles with Nazca Lines cannot be worked, so the best place to build these improvements is 4 hexes away from the City Center - this way, they can enhance the yields of tiles on the periphery of the city's workable area, and the yields provided by Petra are always better than those provided by a Nazca Line anyway.
Situated between the Red Sea and the Dead Sea, Petra is a city cut from the red sandstone around Wadi Musa (now part of Jordan) by the Nabataeans – who obviously had a lot of free time – around 400 BC. Mentioned in Egyptian, Greek and Biblical sources, the city would develop into a major caravan center, a vital crossroads between Arabia, Egypt and Syria to the north. Surrounded by mountains riddled with gorges and canyon passages, it was defensible; but it was the ingenious and extensive system of cisterns and reservoirs in the middle of a desert that made it a trade center. At its peak, Petra was home to perhaps 20 thousand inhabitants, and served as the capital of the Nabataean kingdom. That is, until the Romans arrived and annexed it in 106 AD. Struck by a series of earthquakes, as well as Roman taxes, it was essentially abandoned two hundred years after – not to be “discovered” until 1812 by the Swiss explorer Johann Burckhardt.