Bornholm (Danish pronunciation: [pɒːnˈhʌlˀm]) is a Danish island in the Baltic Sea, to the east of the rest of Denmark, south of Sweden, northeast of Germany and north of Poland.
Strategically located, Bornholm has been fought over for centuries. It has usually been ruled by Denmark, but also by Sweden and by Lübeck. The ruin of Hammershus, at the northwestern tip of the island, is the largest medieval fortress in northern Europe, testament to the importance of its location. Bornholm and Ertholmene comprise the last remaining Danish territory in Skåneland east of Øresund, having been surrendered to Sweden in 1658, but regained by Denmark in 1660 after a local revolt.