Fort Adelaide — locally known as La Citadelle — stands on the hilltop above Port Louis and is the most visible historical landmark in Mauritius, its star-shaped bastion walls visible from most of the city below. Built by the British colonial administration in the 1830s in the years immediately after the abolition of slavery, it occupies a commanding position with 360-degree views over the harbour, the urban core, and the ring of mountains that surround the city.

The fort's history is directly tied to the abolition of slavery. It was constructed specifically to give the colonial government a defensive position from which to control any uprising by the newly freed enslaved population — a garrison from which artillery could command the approaches to the city. The fact that no such uprising occurred does not diminish the story: the fort is a physical expression of the colonial government's fear of the people it had exploited for two centuries.

The architecture is classic star-fort form: angled bastion walls designed to eliminate dead ground and allow flanking fire in all directions. The walls are thick cut stone, well preserved, and the interior parade ground is large and open. There are no interpretation panels beyond a small notice board at the entrance, which means the visit is best done with some background reading in advance — the History Museum in Port Louis is a good preparation.

The views from the ramparts are the best in Port Louis. The harbour stretches away to the north; the city grid spreads below in all directions; the mountains of the Moka Range frame the horizon to the east. Go at golden hour (within an hour of sunset) for the best light on the harbour and the most comfortable temperatures. The walk up from the city takes 30 minutes and passes through the hillside residential neighbourhood of La Citadelle, which has its own quiet charm.