The rambling 18th-century compound known in its day as the 'Gibraltar of the West Indies' was once a major British garrison until it was abandoned in 1850. A major restoration was undertaken in the 1960s and much of the fortress has been returned to its earlier grandeur.

The main hilltop compound, the Citadel, is lined with 24 cannons and provides excellent views of St Eustatius and Sandy Point Town. Inside the Citadel's old barrack rooms are museum displays on colonial history that feature cannonballs, swords and other period odds and ends. There's also a small collection of Amerindian adzes, a few pottery fragments and a rubbing of the Carib petroglyphs in Old Road Town. Brimstone Hill, upon which the fortress stands, is a volcanic cone named for the odoriferous sulfur vents that you'll undoubtedly detect as you drive past the hill along the coastal road.