The Roman theatre of Cádiz is an ancient structure discovered in 1980. The theatre, which was likely built during the 1st century BC and was one of the largest ever built in the Roman empire, was abandoned in the 4th century and, in the 13th century, a fortress was built on its ruins by order of King Alfonso X of Castile.
The theatre featured a cavea with a diameter of more than 120 meters, and could house some 10,000 spectators. The theatre was one of the few Roman structures of ancient Hispania mentioned by classical authors, including Cicero and Strabo. Excavations in the site have also found remains of a quarter dating to the taifa period, Almohad houses and 17th century pits.
References: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.