Perhaps the best known toursit site in Jordan is Petra, a sandstone canyon filled with monuments and tombs sculpted into the cliffs that contain it. Petra was the capital of the Nebateans, an arab tribe that dominated trade between arabia and the west from at least the greek era into the late roman era. Their architecture was a sophisticated pastiche of the styles of their foreign trading partners. The most ornate monuments, including the iconic "Treasury" at the slotted entry to the canyon, are from the late roman period, and exhibit a skill in stonework equal to the roman monuments of the time. Their power diminished as trade routes changed and the late Roman and Byzantine Empires dominated the region, the culture only vestigal by the time of the arrival of Islam.