Karlstad cathedral, which replaced an earlier one in a different location that was destroyed by fire, was built in the 1730 by design of Christian Haller. It is constructed of natural stone and brick which is plastered over. It took around sixty years to complete the interior decorations. The church, which is in a baroque style, has some neo-classical features. It has a light interior.
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.