Only foundations and one gate-tower have survived of the so-called fortified Tafelgut that used to belong to the bishop of Tallinn.
The castle was erected on a hill by the Porkuni lake in 1479 by Simon von der Borch. Cannon towers stood in the corners of the camp castle shaped as an irregular rectangle. The circular wall and the towers did not probably reach their height all at the same time, but in the course of a longer period. This claim is backed up by the gate tower - rectangular at the bottom and octagonal at the top. The machicolation frieze adorning the top of the tower dates back to a much later time, as proved by comparing the engravings of Porkuni produced in the 17th and 19th centuries. The castle was severely damaged during the Livonian War. The castle tower currently houses museums.
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.