Kristiansten fortress
Kristiansten fortress was constructed in 1682-1684 as part of the rebuilding after the city fire 18 April 1682. The main tower is a direct extension of the Cathedral's longitudinal axis, approx. 700 meters away. In the 1700s it was extended to the shape it has today.
In 1816 Karl III Johan decided that Kristiansten fortress should be closed down and be left to deteriorate. The fortress was rescued by the fact that it was decided that the cannons were still to notify the residents in case of a fire, and was therefore needing to be maintained. As part of Trondheim's 1000 year anniversary in 1997, the castle underwent an extensive renovation. Floodlights were installed and one of the fort's underground bunkers, meant for protection of troops, ammunition and supplies, was transformed in to a memorial chapel.