Martello tower built in 1686-1690. The top floor (cannon deck) houses a range of artillery.
The lower floors have exhibitions of the history of Fladstrand and the harbour.
Citadel Fladstrand was used as a base by the Danish Navy during the Great Northern War (1709-20) and the war against Great Britain (1807-14).
In the Powder Tower you are welcomed by historically dressed staff who can tell about the history of the Powder Tower, the relocation in the 70s as well as the maritime history of the harbor, the fleet, Tordenskiold and Fladstrand (today Frederikshavn).