From my perch, I could see a narrow, serpentine road winding down the ridges and gorges. This route, known as the King's Highway, or Darb ar-Raseef ("paved road", in Arabic), is believed to be one of the world's oldest continuously used roads. For millennia, merchants, pilgrims, warriors and kings travelled north to south through Jordan's central highlands, and this thoroughfare served as a vital artery connecting ancient kingdoms and empires.