Located on Kukouri island, Fort Slave is the outermost of the fortifications. The round fortification, made of stone and red brick, was built in 1791-1794.
The outermost and most individual part of the Ruotsinsalmi fortress chain was built on the island of Kukouri off Kotka. This small island formed by a sand ridge was first extended by earth and stone filling. Fort Slava, fort of honour, was completed in 1794. The extraordinary round fortress contained 44 heavy guns. Every second vault provided accommodation space on the side of the inner court. Part of the fortress destroyed by war has been covered