St Cynog's Church in Defynnog contains an ancient stone with Ogham inscriptions. Though most of the attractive building we see today is 15th century, the origins of St Cynog's go back to at least the Norman period if not earlier. There is 11th century stonework in the north vestry wall, and the font and holy water stoup may be 11th century or possibly even pre-Norman. The richly carved font is inscribed with Runic letters, the only example in Wales of a Runic inscription.
The churchyard contains several yew trees, of which the largest has a girth large enough for it to be 1300–3000 years old. An adjacent yew was reported in 2014 to be genetically identical to the largest, leading to conjecture in the popular press that the two trees were remnants of a single 5000-year-old tree; but this conjecture has been disputed on the grounds that layering is a more plausible origin for the adjacent tree. The crown of the largest tree is 60 ft in diameter.
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.