The Peace Palace (Vredespaleis) is an administrative building and often called the seat of international law because it houses the International Court of Justice (which is the principal judicial body of the United Nations), the Permanent Court of Arbitration, the Hague Academy of International Law, and the extensive Peace Palace Library. In addition to hosting these institutions, the Palace is also a regular venue for special events in international policy and law. The Palace officially opened on 28 August 1913, and was originally built to provide a symbolic home for the Permanent Court of Arbitration, a court created to end war which was created by treaty at the 1899 Hague Peace Conference.
References: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.