Venø Church's age is difficult to date but it was probably built around the time of the Reformation (1536), making it the oldest building on the island. According to tradition, it is the smallest church in Denmark measuring only 9.8 by 4.2 meters. The low ceiling and the limited seating capacity (only about 50 places) reinforce this impression. The church is built of fieldstone while brick has been used for the corners and later extensions. There is no tower as the church bell is inside the gable at the west end of the church.References:
Kristiansten Fortress was built to protect the city against attack from the east. Construction was finished in 1685. General Johan Caspar von Cicignon, who was chief inspector of kuks fortifications, was responsible for the new town plan of Trondheim after the great fire of 18 April 1681. He also made the plans for the construction of Kristiansten Fortress.
The fortress was built during the period from 1682 to 1684 and strengthened to a complete defence fortification in 1691 by building an advanced post Kristiandsands bastion in the east and in 1695 with the now vanished Møllenberg skanse by the river Nidelven. These fortifications were encircled by a continuous palisade and thereby connected to the fortified city. In 1750 the fortress was modernized with new bastions and casemates to protect against mortar artillery.