Alcalatén Castle, located on San Salvador Mountain in the municipality of Alcora, is an Islamic fortress with medieval architectural reforms, built between the 10th and 13th centuries.
In 1233, after the conquest of Borriana, King James I granted the castle and the title of baron to the Aragonese knight Ximén d'Urrea.
The castle, with a triangular layout, covers an area of 150 square meters. It includes a main enclosure surrounded by a patrol path, with a cistern, as well as both abandoned and inhabited areas.
At the highest point, two walls forming a right angle and topped with battlements are preserved, extending into two towers; one circular to the north and one semicircular to the south. A third tower is known to have existed, though only rubble remains from its demolition in the 15th century. The eastern section is completely destroyed. At the base of the citadel, a rectangular cistern made of mortar and stones remains, measuring approximately 4 by 10 meters. The structure is built with masonry.
The entrance is on the south side, featuring two circular towers, battlements, and a barbican-style wall.
Towering 52 meters above the sea, Bengtskär lighthouse is the tallest one in Scandinavia. The building started in in 1905 after the shipwreck of S/S Helsingfors and was completed in 1906. The lighthouse was designed by architect Florentin Granholm. On December a special petrol lantern, designed and built in Paris, was brought to Bengtskär and installed atop the tower.
German fleet bombarded Bengstkär in the First World War in 1914. Since the Gulf of Finland was heavily mined, it was not until 1919 that the surrounding seas were declared safe for shipping, that the light was lit again.
After the war the military value of Bengtskär increased as part of the defence system of independent Finland. In Second World War (1941) Soviet Union made a suprise attack to island. After a bloody battle, the small Finnish garrison emerged victorious. Intermittent repairs to the facility continued during the post-war period.