Mada'in Saleh was known as Hegra by the Nabataean people who carved its magnificent tombs into the golden Quweira sandstone outcrops. They were also known for their incredible familiarity with the desert and their ability to fade into it to evade enemy tribes. Their system of hidden cisterns dug deep in the interior provided water for their livestock and their people. The real cause of the success of the Nabataeans, however, was control over much of the spice trade. Many spices from southern Arabia were brought up to the north along trade routes to be purchased by people around the Mediterranean and in the Near East. The details on the entrance portals and the smooth surfaces of its 111 tomb façades reflect the great skills of the masons of the Nabataeans' time. The splendor of the natural setting here must have reminded the Nabataeans of their capital, Petra. It is no wonder that they chose this very spot to build their second city, Hegra, because it was a crossroads where the major north-south incense route intersected a road from the Red Sea to the Persian Gulf. The ruins of the town of Hegra lie on the plain some distance from their tombs. The buildings, still for the most part unexcavated, were made of unimpressive sun-dried mudbrick. What is known about Hegra comes primarily from the tombs, the many inscriptions carved into their façades, and references found elsewhere. The tomb façades are finely carved and fairly uniform in their style. A portal in the center of the façade provides the entrance to the tomb. Inside are recesses carved into the walls where the bodies of the deceased were placed.