The Trier Imperial Baths (Kaiserthermen) are a large Roman bath complex, designated as part of the UNESCO World Heritage Site. The impressive ruins of the baths, along with the derelict rooms and the walls of previous structures, are among the most important to have been discovered in Trier. Today a visit to the thermal baths, which can also be explored below ground, is like stepping back in time. The walls of the hot bath (caldarium) are deservedly part of this famous landmark in Trier. After the one in Rome, the Imperial Thermal Baths and St. Barbara Roman Baths were once among the largest bathing complexes in the Roman empire. They were built in the first and second centuries AD.
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.