The Al Ayjah Watchtowers stand over the old fishing quarter across the lagoon from central Sur. They are small, round, and simple, but their position explains their value: from here you can read the harbor, the bridge, the creek, and the coast that made Sur a dhow-building town.
Come near sunset if you can. The towers work best as a viewpoint and orientation stop, not as a museum. Combine them with Al Ayjah Fort, the lighthouse area, and a look at the dhow yards to understand why this corner of Oman looked outward to the sea for so long.