Fort Napoleon in Ostend is a polygonal fort built in the Napoleonic era. It has recently been restored and is open to the public.
France had occupied the Austrian Netherlands (a territory roughly corresponding to the borders of modern Belgium) during 1792 and 1793 in the Flanders Campaign of the French Revolutionary Wars. During the War of the Fifth Coalition, Napoleon Bonaparte expected a British assault from the sea on the port of Ostend, and the fort was constructed in the sand dunes close to the mouth of the harbour in 1811. The British attack never materialised and the fort was used as for troop accommodation and as an arsenal until the end of the French occupation in 1814 when it was abandoned.
During World War I, the fort was used as accommodation for a German headquarters, and decorated with murals by German soldier Heinrich Otto Pieper. The heavy coastal artillery battery Hindenburg was stationed nearby. It was armed with four 280 mm guns of 1886-1887 vintage in heavily armored turrets on semi-circular concrete platforms. It was captured by the Belgian army in 1918.
The fort was also used as German artillery headquarters during World War II. After the war, it served as a museum and then a children's playground before falling into decay. In 1995, the fort was restored and opened to the public in 2000.
References:Château de Niort is a medieval castle in the French town of Niort. It consists of two square towers, linked by a 15th-century building and dominates the Sèvre Niortaise valley.
The two donjons are the only remaining part of the castle. The castle was started by Henry II Plantagenet in the 12th century and completed by Richard the Lionheart. It was defended by a rectangular curtain wall and was damaged during the Wars of Religion. In the 18th century, the castle served as a prison.
The present keeps were the central point of a massive fortress. The southern keep is 28m tall, reinforced with turrets. The northern tower is slightly shorter at 23m. Both are flanked with circular turrets at the corners as well as semicircular buttresses. Each of the towers has a spiral staircase serving the upper floors. The Romanesque architecture is of a high quality with the dressed stones closely jointed.