A church at the site of current Santa Marta was present by the 13th century, originally dedicated to St Calimero. In 1386, it housed the flagellant Confraternity of the Disciplini of St Marta, who added a hospice and rededicated the church. The church has been refurbished over the centuries. The facade dates to 1720–1730.
The interior ceiling has a late 17th-century fresco, depicting the Glory of St Martha, by Giovanni Battista and Carlo Pozzo, and the church houses a 17th-century processional statue on the main altar of the Madonna of the Rosary and Child. The altar has 16th century marble sculpture busts of the apostles; the altar was refurbished in 1816 likely by Giuseppe Bovara. The lateral altars have statues of Santa Marta and San Antonio di Padova.
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.