The St. Henry's Chapel is a medieval wooden barn, which was surrounded by the present brick chapel in 1857. According the legend St. Henry, the first bishop of Finland, spent his last night in the barn before local peasant Lalli murdered him in 1156. Although according modern archeological investigations oldest parts of the barn were made in 1472-1473. Oldest records from the 17th century tells that the barn has been a destination for local pilgrimages.
Senate of Finland decided to protect the barn as the national heritage in 1839. Architect Pehr Johan Gylich designed the chapel around barn to shelter it. The chapel was inaugurated in 1857.
The chapel is open to the public in July with no admission fee.
Bomarsund fortress and garrison was built in 1832-1854 by Russian Empire to defence Åland Islands against enemies. British and French fleet attacked against it during the Crimean War in 1854. After a week of fighting the British stormed the remaining fort. Anglo-French forces destroyed it totally after battle. In the Treaty of Paris 1856, the entire Åland Islands were demilitarized, which is a status that has been preserved until this day.
Nowadays there are some ruins left and fortress area is open for visitors.