Petra

Petra is an ancient city carved into rose-colored sandstone cliffs in Jordan's Ma'an Governorate, built by the Nabataeans beginning in the fourth century BC and serving as the capital of the Nabataean Kingdom from the second century BC. Its best known monument, Al-Khazneh, or the Treasury, is a facade cut directly into the rock face, about 24 meters wide and 37 meters tall, believed to have served as a mausoleum for King Aretas IV. The city is renowned for its rock-cut architecture and engineered water conduit systems, which allowed a substantial population, estimated near 20,000 at its first-century AD peak, to thrive in an arid valley. Largely unknown to the Western world after antiquity, Petra was located again in 1812 by the Swiss traveler Johann Ludwig Burckhardt, and UNESCO inscribed it as a World Heritage Site in 1985.