The Onze-Lieve-Vrouwetoren ('The Tower of Our Lady') is a Late Gothic church tower which is 98.33 metres tall and reaches high above the inner city. It's one of the most eye-catching monuments in town and the third highest church tower in the Netherlands. The church that belonged to the tower was destroyed by a gunpowder explosion in the 18th century.
The first chapel on site was constructed on this site in the 14th century. In the 15th century the chapel was replaced by new church with three aisles. When the tower was built is not exactly known. Construction started around 1444 and was finished around 1470. The official documents of the construction were destroyed by the Protestants in 1579 during the reformation and the ensuing iconoclasm. The church and tower were taken over by the Protestants and no longer belonged to the Catholics.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.