Built in 1535, with additions made in 1541, this massive, well-preserved Portuguese fort with its double moat (one tidal) must once have been impregnable, but sea erosion and neglect are leading to a slow collapse. Cannonballs litter the place, and the ramparts have a superb array of cannons. The lighthouse, which you can climb, is Diu’s highest point, with a beam that reaches 32km. There are several small chapels, one holding engraved tombstone fragments.
Part of the fort also serves as the island’s jail.