Kärnan (Swedish pronunciation: [ˈɕæ̂ːɳan]; Danish: Kernen, both literally The Core) is a medieval tower in Helsingborg, Scania, in southern Sweden. It is the only part remaining of a larger Danish fortress which, along with the fortress Kronborg on the opposite bank of the Øresund, controlled the entranceway between the Kattegat and the Øresund and further south the Baltic Sea.[1]