Oscarsborg Fortress Museum Oscarsborg Fortress is one of the most important historical fortifications in Norway. The Kaholmen Islands has been used for military purposes since 1640’s because of their strategic position in the Drøbak Sound where the Oslofjord is at its narrowest.The task of the museum is to present the history of the fortress, with emphasis on the incidents of the 9th of April 1940. It also conveys the history of the Coast Artillery and its technical developments. The Coast Artillery was abolished as a self-contained service in 2002.The exhibitions of the Museum The various exhibitions show the different stages in the history of the fortress and the Coast Artillery.The principal exhibitions are located in the eastern part of the main fort.The old casemates in the outer building contain exhibitions that present the recent history of the coast artillery.On North Kaholmen the Torpedo battery which gave “Blücher” the deathblows early in the morning on the 9th of April 1940 can be visited.Guided tours The Museum offers guided tours throughout the year. The public can choose themed tours last- ing from half an hour to two hours: Standard Tour, “1940”, Torpedo Battery, Older History, Artilleristic,Mess History, the Defence House/ Commandant House. Tours can be combined but we recommend a total duration of no more than two hours. The admittance to the museum is free, but charges apply for guided tours.See www.oscarsborg.no for more details.Opening hours and contact The Museum is open every day (except for festival days) from 10 o’clock till 16 o’clock. The Torpedo Battery and the Fire Control Museum is open only in connection with guided tours.Booking office of the Museum will serve the acco- modations for guided tours. The office opening hours are every weekday from 09.30 until 14.30.In the winter season from 1st of October until 30th of March the office will be closed Monday and Friday.