4. Petra, Jordan

Petra was the ancient capital of the Nabataean kingdom. A city carved in stone, into the side of the Wadi Musa. The city was possibly established as early as 312 BC and flourished for a long time as it was important junction for the silk and spice routes that linked the East and the West. The city fell to decline and was finally abandoned in the 6th century, after a series of earthquakes ruined its water supply. The important and beautiful city was eventually forgotten. It was discovered to the Western world only in 1812