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:Carlsten is a stone fortress built on the orders of King Carl X of Sweden following the Treaty of Roskilde, 1658 to protect the newly acquired province of Bohuslän from hostile attacks. The site of Marstrand was chosen because of its location and its access to an ice free port. Initially a square stone tower was constructed, but by 1680 it was reconstructed and replaced by a round shaped tower. Successive additions to the fortress were carried out, by the inmates sentenced to hard labour, until 1860 when it was reported finished. The fortress was decommissioned as a permanent defense installation in 1882, but remained in military use until the early 1990s.
The fortress was attacked and sieged twice falling into enemy hands. In 1677 it was conquered by Ulrik Frederick Gyldenløve, the Danish military commander in Norway and in 1719 by the Norwegian Vice-Admiral Tordenskjold. At both occasions the fortress was returned to Swedish control through negotiations and treaties.