JEDDAH: On a lonely exposed hillside a few kilometers outside the capital of Al-Jouf province, Sakkaka, stand clusters of three-meter high fingers of stone. Etched with ancient Thamudic graffiti, these monuments to a long extinct culture have maintained their lonely vigil for six millennia. Many have fallen over and others lean at bizarre random angles. Al-Rajajil ("the men"), the sandstone stele weighing up to five tons each, is popularly called Saudi Arabia's Stonehenge. They are possibly the oldest human monuments on the peninsula. Some time in the Chalcolithic, or Copper Age, people living in the area where Al-Jouf is today...