Examine an ancient dam network built to protect Petra’s “Treasury” monument from potentially damaging and deadly flash floods, in this video from NOVA: Building Wonders: Petra. A Swiss architect and archaeologist explains that clues in the landscape suggest that a reservoir, dug channels, and dams once worked together to spread out wintertime flood water that otherwise would have threatened the elaborate façade. The design was so perfect that today a team is repairing the dam network so it can once again protect this important ruin.