Pen Dinas is the name of a large hill just south of Aberystwyth where an extensive Iron Age, Celtic hillfort of international significance is situated.
The hillfort actually consists of two separate forts built many years apart, which were later combined to form a larger structure. The first fort to be constructed was on the lower northern summit. It consists of an outer ditch and inner rampart of rubble. It would originally have been surmounted by a wooden palisade. The main gateway is on the western side and is formed by a stone lined gap in the ditch and bank.
After this first fort was eventually abandoned several decades passed before work began on a new fortification on the higher summit to the south. This second site is better protected by a steeper slope on the western side. To the south and east huge terraced earth works were built faced with shale which would again have been topped with a wooden palisade. Entrance into the southern fort is via gateways to the north and south. They are both formed of narrow passageways through the earthworks and would also have had timber bridges to cross the ditches. The northern gateway is kinked to the left, probably to aid defence by slowing down attackers.
Eventually the southern fort too became derelict and there is evidence that some of the wooden structures by the northern gateway were burnt. This could be following a hostile raid on the fort or because lack of resources lead to its abandonment. However, sometime later the defences of the southern fort were rebuilt this time to a different layout.
The final phase in the fort's construction was the refortification of the northern section and the construction of banks and ditches to connect the two forts together thereby enclosing the entire hill top. The coming of the Romans to the area in about 74 AD may have led to the forcible abandonment of the fort or it may have fallen from use before then but the only evidence from the Roman period is an early 4th-century coin hoard of Roman currency possibly left as an offering to a shrine on the hill.
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.