One of the best-preserved examples of Dutch military architecture in Indonesia, Fort Rotterdam was built on the site of a Gowanese fort, itself built to repel the Dutch East India Company. Having failed to keep out the orang belanda, it was reconstructed by the new masters of Makassar after their 1667 conquest, and includes many fine, well-restored colonial structures. You can walk the enclave's stout ramparts, see sections of the original walls and visit the Museum Negeri La Galigo, inside.
While foreign visitors tend to marvel at the architecture, local tourists remember the fort as the final residence of national hero Prince Diponegoro who led the rebellion in Java against Dutch occupation. He was imprisoned here for 25 years until his death in 1855.