Masada was built on a rhomboid-shaped plateau. The top surface measures about 2,132 feet long by 984 feet wide. The isolated escarpment (technically a horst) was formed when a geologic fault plus erosion separated it from the neighboring ridges. The sibling mound in the west is Wadi Ben Yair. Shown here is the much larger Wadi Masada flanking the east and south.