What is Petra, the city carved into rock?

Deep in the desert of Jordan, there's a city hidden inside cliffs — a real city, carved straight into rose-colored rock two thousand years ago. You walk through a narrow crack in the mountains, and suddenly: temples with columns, tombs as tall as office buildings, theaters and houses, all chiseled from the stone itself. This is Petra, and it shouldn't exist.
Around 300 BC, a group of traders called the Nabataeans controlled the crossroads where caravans traveled between Arabia, Egypt, and the Mediterranean. Spices, silk, incense — everything valuable passed through their territory. They got rich charging tolls and selling water. But where do you build your capital when you're surrounded by enemies who want your wealth?
