Between 1612 and 1615, Salzburg’s prince-archbishop Markus Sittikus commissioned the building of a summer residence at the foot of Hellbrunn mountain, a location already abundant in naturally flowing waters. Based on Italian models and in a relatively short period of time, an architectural jewel had been created, still reckoned amongst the most magnificent Renaissance buildings north of the Alps. Hellbrunn was only meant for use as a day residence in summer, as the Archbishop usually returned to Salzburg in the evening, therefore, there is no bedroom in Hellbrunn.
The schloss is also famous for its jeux d'eau ('watergames') in the grounds, which are a popular tourist attraction in the summer months. These games were conceived by Markus Sittikus, a man with a keen sense of humour, as a series of practical jokes to be performed on guests. Notable features include stone seats around a stone dining table through which a water conduit sprays water into the seat of the guests when the mechanism is activated, and hidden fountains that surprise and spray guests while they take part on the tour. Other features are a mechanical, water-operated and music-playing theatre built in 1750 including some 200 automata showing various professions at work, a grotto and a crown being pushed up and down by a jet of water, symbolising the rise and fall of power. At all of these games there is always a spot which is never wet: that where the Archbishop stood or sat, to which there is no water conduit and which is today occupied by the tour guide.
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.