Petra

Arguably the most beautiful of all the cities on this list, Petra is located in Jordan near the Dead Sea and is believed to have once been the center of the Nabataean caravan trade. Its most striking feature is its exquisite stone architecture, which is carved out of the rocks of the surrounding mountains. This helped make Petra a naturally fortified city when it was established as a capital in 100 B.C., and evidence suggests that it featured many other technological advancements like dams and cisterns, which helped the inhabitants channel the region’s flash floods and store water for use in times of drought. After hundreds of years of prosperity, the city went into decline after the Romans conquered the region, and in A.D. 363 an earthquake destroyed several of its buildings and crippled its infrastructure. Petra was eventually abandoned, and it stood for years in the desert as something of a curiosity before being revealed to the world at large in 1812 by a Swiss explorer.