Castles, forts and buildings with high walls formed architectural styles characterized by immunity and architectural thickness, which prevents strangers from entering the places where the castles are located. They were originally built to protect lands, cities and countries from foreign occupiers. Castles are spread in various parts of the world since ancient times, when wars occurred face to face with various old weapons. The castle was one of the most important means of defense in past times, for protection from enemies. Its task varied between being a house, a fort, a prison, and a warehouse. They were often built in remote areas, which no one could reach, built on mountain peaks, or overlooking the sea, and rarely on flat land. The various regions of the Kingdom are filled with a large number of castles and forts reaching (78) castles and forts, this is besides the immune houses and palaces that played the role of the castle in protecting and defending villages, cities, and pilgrimage and trade routes. In Dumat Al-Jandal, there is the oldest castle in the Kingdom built three thousand years a.