Fort Boyard is a fort located between the Île-d'Aix and the Île d'Oléron in the Pertuis d'Antioche straits, on the west coast of France. Though a fort on Boyard bank was suggested as early as the 17th century, it was not until the 1800s under Napoleon Bonaparte that work began. Building started in 1801 and was completed in 1857. In 1967, the final scene of the French film Les aventuriers (1967) was filmed at the remains of the fort.
Fort Boyard is oval-shaped, 80 metres (260 ft) long and 40 m (130 ft) wide. The walls were built 20 m (66 ft) high. At the Centre is a yard, and the ground floor provided stores and quarters for the men and officers. The floor above contained casemates for the emplacements of guns and further quarters. Above that were facilities for barbette guns and mortars.