Rising without competition from the surrounding plain, Jabreen Castle is an impressive sight. Even if you have had a surfeit of fortifications, it's worth making the effort to clamber over one more set of battlements – Jabreen is one of the best-preserved and whimsical castles of them all. Head for the flagpole for a bird's-eye view of the latticed-window courtyard at the heart of the keep; the rooms here have distinctive painted ceilings.

　　Built in 1675 by Imam Bil-Arab Bin Sultan, Jabreen Castle was an important centre of learning for astrology, medicine and Islamic law and, unusually for Oman's forts and castles, there's quite a lot to discover inside the vast battlements. There is an interesting date store, for example, to the right of the main entrance on the left-hand side. The juice of the fruit would have run along the channels into storage vats, ready for cooking or to assist women in labour.

　　The most interesting feature of this castle is the elaborately painted ceilings. Several rooms, that seem to spring illogically from different courtyards in the heart of the keep, sport ceiling timbers with the original floral motifs. Finding these hidden rooms is part of the fun – and the original defensive mechanism – of Jabreen. Try to locate the burial chambers, remarkable for their carved vaults, and the room earmarked for the sultan’s favourite horse.

　　Jabreen's location, trapped between the mountain and a particularly arid part of the desert, roasts under a ferocious sun for much of the year, hence the falaj (irrigation channel) running through the outer courtyard, which was not used for water supply but as an early air-con system.