Al Suwaiq Castle:-

Al Suwaiq Castle lies atop a hill, 200 meters off the sea . It is a rectangular building, 78 meters in length and maximam 47 meters in width, with three round towers at the corners, one forth square tower at the north-west corner and a fifth rectangular tower in the south. The Castle was used defensive purposes and as headquarters for the Wali. It was restore during the period ( 1992 - 1994 ) and again in ( 1998 ) . It was converted into a tourist monument . 

Al Tharmad Castle

Al Tharmad Castle is a square shaped building, 37.5 meters in length and width. It has four towers of different shapes, round and square , and the main entrance lies at the north facade behind another facade for more protection. The walls have elevated battlements,and there are small apertures for attacking and opening fire,The Castle is surrounded by a moat from three directions , and was used mainly for protection purposes. 

Nakhl Fort :-

Nakhl Fort dates back to the pre-islamic era, and was built in a naturaly protected strategic location at top of rocky hill that is 61 meters high, which distingushed it from the other forts in Oman . It was designed for defensive purposes, surrounded by high walls, with seven watch towers, one of which lies at the courtyard , and the other six are scattered across the walls. The Fort also has a Masjed and other multipurpose rooms. The ceilings, doors and windows are decorated and engraved. The Fort was once used as a seat for the political and administrative authorities at the Wilayat.

Nizwa Fort and Al Aqar Castle

Built by I mam Sulatn bin Saif al Ya'arubi and it took some 12 years to be completed . The Fort is of round shape, and was firmly built to withstand the vibration from firing the cannons. Built by Imam Al Salt bin Malik Al -Kharusi , Al Aqr Castle that surrounded the Al Shahba  Fort was renovated by the first Ya'arubian Imam Nasser bin Murshid. Located at the middle of the city, the castle is a quadrangle walled structure that is surrounded by a 9 meter-high wall with apertures for cannons. There are seven wells mouths still in operation  up to date. The Castle was once used as the Imam's headquarters and as a stronghold in times of war . The Fort and Castle were renovated during the glorious era of the Omani during the period ( 1988 - 1990 ) and was converted  into a tourist monument .

Oman forts  and castles

A fort : A military stronghold overlooks a strategically location such as mountains,hills,rocky hillocks or beach coasts that is used for defensive and surveillance purposes. Usually, it consists of watchtowers, apertures for shooting arrows and canons along with other military structures. The inhabitants of the fort are always soldiers or military people only. A castle may contain a fort or more but a fort is a separate unit that might within or outside the castle.

A castle : A building surrounds an area of land to protect and defense it from enemy attacks. It is the biggest military stronghold but not the strongest. Thus, city walls were known as castles in the middle ages. What distinguishes them from normal wall is they have parts which are designed especially for surveillance  and  protection such as towers, and lookouts stations.In Oman, most of the castles were used as residency for Imams, Sultans,princes and Walis till the early 20th century. They were the center of the century. They were the center of the traditional ruling system. Citizenry lived within their walls.

Al Rustaq Fort : -

Considered as the second biggest fort in Oman and one of the heighest , Al Rustaq Fort was built by the Azid's kings after they settled in Oman . Other refrences state that it was built by the the Parsians before the breakout of Islam. It is also said that it may had been built on the beginning of Al Ya'ribah reign. The Fort is a triangular building arched , it is characterized by the impreg-nable fortification and the four entrances . Its walls are as high as the watchtowers, which are (11) in number , and some of them have names, such as "Burj Al Reeh " (Tower of Wind ) , " Al Burj Al Ahmar" ( Red Tower ) and "Burj Al Hadeeth" (New Tower ). It was once used as the seat for the political and administrative authorities . It was restored several times was converted into a tourist monument .