The Nabateans, were hydrological geniuses. Their remarkable skills in locating, trapping and storing water in a brutal desert gave them a monopoly over the one item absolutely essential to caravan trade. The city that managed to own the franchise on all the water stops in the desert could, and did, set their own terms when it came time to tank up the camels. And despite this, by the middle of the 7th Century, the ancient site of Petra had become an abandoned and ghostly ruin, occupied only by nomadic herders. Today, the site is visited by tourists who come from all over the world to drop their jaws at the sight of these palatial remains. But by night, the city is empty, though guards whispered about ancient magic and phantom voices can be heard over the desert winds. Recently, several archaeologists reported that they caught sight of moving figures and inky shadows that raked along the high canyon walls. In one case, a team was driven out of the city by the sounds of screams in the darkness. It is believed that the canyons are haunted, both by the Nabateans themselves and by the mystical magic they practiced.