Petra, located in Jordan, is an ancient city carved into rose-colored sandstone cliffs that was once the capital of the Nabataean Kingdom. For centuries, the city's existence was unknown to the outside world until it was rediscovered in 1812 by a Swiss explorer. The impressive structures like the Treasury and the Roman-style theater were carved by the Nabataeans between the 6th century BC and 1st century AD. At its peak, Petra had over 30,000 inhabitants and was a major trading hub, but a powerful earthquake in the 6th century CE destroyed much of the city, after which it was abandoned.