In the mountainous regions, stone is the most predominant building material. In the high plateau areas, both local mud and nearby imported stone form a hybrid of construction materials. All Yemeni buildings exhibit superb craftsmanship in a tradition of mud and stone masonry that has been maintained for centuries. This dense, walled city projects the urban character typical of traditional Arab cities and contains many building types unique to Southern Arabia. The most striking of these is the tower house, which looms above as one walks through the narrow, winding streets of the old city.
Most tower houses are at least five stories high, and some reach as many as eight or nine.
Their origin lies in the remote villages where farmland was scarce and verticality was the only means of accommodating the settlement of people with efficient use of the land. Height also provided the necessary overview to protect a settlement and its crops from marauding tribes. That tower houses existed during pre-Islamic times is proven by the historical accounts of the Ghumdan palace, built in the third century A.D. and later destroyed in the seventh century. It was described as a grand palace, as tall as 20 stories, with each wall built of different colored stone and including a top room with an alabaster ceiling and windows built of marble, teak, and ebony. The vertical arrangement of these multi-storied houses represents an upward transition from public to private space.