The most notable among these are Wadi Hadhramaut and Wadi Dawan, in eastern and central Yemen.
The undefined northern edge of Hadhramaut slopes down to the vast drydesert of Rub al Khali.
The upper portions of Wadi Hadramaut contain alluvial soil and floodwaters while lower portion is barren and largely uninhabited.
Haid Al-Jazil, a village perched entirely on a boulder.
Many of them hang above the rocks.
The houses are build of mud bricks with wooden floors and rises several stories tall.
Shibam.Photo credit
Lying adjacent to Wadi Hadramut is another spectacular place - Wadi Dawan.
One of the biggest villages in the wadi, called Sif, lies next.
Yemen was one of the oldest areas of human civilization, yet remains one of the poorest Arab countries.
