Saint-Louis sits at the mouth of the Senegal River, four hours north of Dakar. The historic core — a long, thin island connected to the mainland by the Pont Faidherbe — is a UNESCO World Heritage Site, with crumbling colonial buildings, art galleries, and one of West Africa's most atmospheric jazz festivals every May.
What to see
The Pont Faidherbe itself is a Gustave Eiffel design and worth a walk. The Musée du CRDS covers the history of the city. Langue de Barbarie National Park, a thin sandbar across the river mouth, is a major bird sanctuary.
When to come
May, for the Saint-Louis Jazz Festival — one of Africa's biggest — if you can plan ahead. Otherwise, December-February for cool, dry weather.