The Citadel

About

The Citadel of Montreuil‑sur‑Mer, a 16th‑century star‑shaped fortification built atop the ruins of a 13th‑century royal castle, offers visitors a vivid journey through France’s military history. Its imposing walls, two grand towers, and the renowned “Port de la reine Berthe” provide sweeping views of the Oise river basin. The site blends historic architecture with a unique ecological role: it serves as a vital hibernation haven for rare bat species, earning its designation as a Natura 2000 site. Guided tours—available in several languages—take guests through the citadel’s storied chambers, including the “Chasse aux trésors” immersive scavenger hunt, while the free‑entry “Visite libre” lets visitors explore at their own pace. With an entrance fee of €7.50 for full admission (reduced rates €5.00 for students, seniors, and groups over 15), the Citadel is accessible to families, history lovers, and urban explorers alike, offering a blend of cultural heritage and nature conservation in the heart of Normandy’s seaside town.

At a glance

• Typical visit: about 1 hour 30 minutes

Tickets & pricing