Hammershus is a castle and a system of fortifications on Bornholm and is the largest fortress in northern Europe. The castle was built by the Danes in 13th century on the Hammeren massif (the name of the castle originates from it). The castle’s fortifications are located on a rocky cliff; they consist of walls, ramparts and a moat. Inside of the castle the observatory tower was erected, which originally had six floors (at present there are half of them existing).
