The other Another type of columbaria, which is rarely preserved as well as the caves, is a tower columbarium. These are usually round but sometimes square. The example from Abu Haf (6 mi north of modern Beer Sheva) shows many of the typical features, although it survives to a height of only a few feet. The round structures probably stood about 15–20 feet high and often had one or two interior cross walls to support the roof and create more wall space for niches. There was no door at ground level (it was located several feet up the wall and accessed by ladder) and the entire exterior was plastered smooth to prevent predators from entering.