The large earth-filled circular tower of Nizwa is unique in Oman. Constructed by Imam Sultan bin Saif bin Malik Al Ya'arubi circa 1660 CE, it is connected to a labyrinthine castle. Adjacent to the fort and castle complex is Nizwa's traditional souq, famed for its thriving craft industries.

A remarkable blend of defensive architecture and sophisticated artisry, the exquisite palace at Jabrin was constructed circa 1670 CE at the height of the Ya'aruba dynasty - a period of peace and prosperity. Today, majestic in its solitude, Jabrin continues to dominate the local landscape, projecting an area of power and solidity.

The 17th century bastion of bayt al Ridaydah is located approximately 24 Km from Nizwa at the beginning of Wadi Muaydin. Combining the traditional elements of defensive and vernacular architecture, its thick, turreted perimeter walls of mud brick belie an elegant interior featuring polylobate arches, painted ceilings and elaborate plasterwork.

Al Rustaq Fort nestles at the foot of Al Jabal Al Akhdar on the edge of the Batinah Plain. Originally constructed on Persian ruins circa 1250 CE, the imposing present-day structure was rebuilt by the first ruler of the Ya'ruba dynasty in 1650 CE. Additional towers were completed in 1744 and 1906 CE.

The magnificent military stronghold at Al Hzam makes full use of traditional Omani defensive features, boasting a massive wooden entry door, secret escape tunnels, dungeons, cannon towers, gun ports in the upper floors, and a machicolation above the entrance for pouring boiling oil or date syrup onto unwary attackers below.

Spectacularly perched on a rocky prominence in the foothills of the Western Hajar, Nakhal's 17th-century fortress stands guard over verdant palm plantations and commands a superb 360-degree view of the surrounding countryside. Nakhal is famous for its mineral-laden hot springs, which flow year-round from clefts in the mountain rock.

The construction of Bayt al Naman is among the many achievements of the political and economic renaissance that look place in Oman under the Ya'aruba Imams (1624-1741 CE). Serving as a residence and a resthouse for distinguished travelers this country stronghold continued to be used until a few decades ago.

A major landmark on the Batinah Cost, Barka Castle is located only a few hundred meters from the shore of the Gulf of Oman. It features an unusual octagonal tower, and at the rear of the castle are two restored watchtowers, which were once part of the defensive town wall.

Located west of Barka on the Gulf of Oman, As Suwayq Castle is distinguished by three round corner towers, the forth corner being occupied by a square keep in the style of pre-cannon architecture. In the early 1800's the castle was famously defended by the wife of Wali of Suwayq.

The Castle stronghold at Al Mintarib stands guard over a fertile date palm oasis on the fringes of the Sharqiyah Sands. The sands are home to large populations of migratory Bedouin who congregate in Al Mintarib and Other oasis towns from June to September of each year during the annual date harvest.

Sunaysilah Castle stands high on a knoll overlooking the seafaring and boat-building town of Sur. Based on an archetypal square plan with round towers at each of its four corners, this dominating fortress is said to be more than 300 years old.

The castle at Bilad Sur, known for its unusual tower, is surrounded by lush groves of date palm. Strategically positioned inland from the sea to protect against raiding tribes from the interior, the fort is part of a comprehensive network of regional defense that originally comprised five fortresses and numerous watchtowers.

The stronghold at Ras al Hadd holds away over a sandy spit of flat, coastal land that marks the easternmost corner of the Arabian Peninsula. As a site of early settlement and a landfall for ancient seafarers, the headland is a focus of attention for archaeologists. It is also an important nesting ground for thousands sea turtles.

The castle at Jaalan Bani Bu Hasan was built as part of a system of fortification that once included an extensive town wall. The town itself is famous for its Arabian horses, and for the skill of its riders-which are displayed in association with weddings, festivals and other celebratory events.

Al Hillah Castle, notable for its distinctive plasterwork motifs, is situated at the heart of Buraimi Oasis. The strategic position of Buraimi on the overland route from Sohar to the Gulf made it a center of conflict in centuries past and has imbued it with a fascinating history.

Al Khandaq Castle in Buraimi is the most famous example of an entrenched stronghold in Oman. The use of a defensive trench or 'dry moat' is an ancient strategy, which has been employed in the protection of Omani cities, fortresses and castles since before the arrival of Islam.

Ibri is one of the oldest inhabited areas in Oman. Ibri Castle, a remnant of the original walled city, is a robust structure built to withstand time and a harsh environment. Within its perimeter walls is the Friday Mosque, beautifully restored, which continues to be used by townspeople to this day.

The coastal community of Qurayyat is located 80 km from the Capital Area at the terminus of a spectacular mountain drive. Just inland from the sea, Qurayyat Castle protects the town center and surrounding palm plantations. A unique triangular watchtower, perched atop a small rocky islet, stands guard over the harbor area.

Khasab Castle, a picturesque stronghold situated on the inner cove of Khasab Bay, was built in the 17th century by Portuguese invaders seeking dominion over regional maritime trade. Contained within its low, crenellated walls is a massive central tower, which is thought to pre-date the castle itself.

Nested in the heart of a coastel Dhofari town famed for its pottery, silverwork and other artisanal industries, it should come as no surprise that Taqah Castle has an artistry all its own. The castle's numerous shuttered windows are particularly distinctive, being fitted with latticed wooden screens and keyhole-shaped arches.

The old incense port of Mirbat is remarkable for being the site of one of the last battles in the world involving conventional attack and defense of a fortress. The well-documented and fiercely fought battle at Mirbat Castle was a milestone in the Dhofari insurrection of the mid-1970, and is credited with saving both the port and the town.

The castle at Sadah is the easternmost of a string of fortifications protecting the Dhofar coast. Despite its remote location Sadah is a prosperous community, boasting a thriving traditional abalone fishery and a history of lucrative incense trade. The homes of wealthy myrrh merchants still stand on the foreshore of the town.