I have long wanted to go there (a sign that it isn’t actually a good standard tourist site) and now I read it is the focal point of the new promotion of tourism in Haiti:
The Western Hemisphere’s largest fortress, it was built atop a 3,000-foot mountain in the tumultuous years after Haiti broke from France in an 1804 slave revolt and became a symbol of triumph over bondage for descendants of African slaves everywhere.
The trip there is a two-hour crawl over unpaved roads and through garbage-strewn, traffic-clogged streets of Cap-Haitien. The final ascent, a steep cobblestone path, is traversed on foot or on undersized horses beaten with sticks by local guides.
Here is a painting of The Citadel.