Maguelone Cathedral stands on an isthmus between the Étang de l'Arnel lake and the Mediterranean Sea in the Gulf of Lion, which was once the site of the original city of Maguelone, opposite the present-day town of Villeneuve-lès-Maguelone.
Maguelone Cathedral was once the episcopal seat of the former Bishop of Maguelone until 1563, when the see was transferred to the newly created Bishopric of Montpellier. The cathedral, constructed when the see was returned here in the 11th century from Substantion by Bishop Arnaud (1030-1060), is a Romanesque fortified building. Although parts, such as the towers, have been demolished, the main body of the building remains functional and is a registered national monument.
References:Bomarsund fortress and garrison was built in 1832-1854 by Russian Empire to defence Åland Islands against enemies. British and French fleet attacked against it during the Crimean War in 1854. After a week of fighting the British stormed the remaining fort. Anglo-French forces destroyed it totally after battle. In the Treaty of Paris 1856, the entire Åland Islands were demilitarized, which is a status that has been preserved until this day.
Nowadays there are some ruins left and fortress area is open for visitors.