The Callanish Stones are an arrangement of standing stones placed in a cruciform pattern with a central stone circle. They were erected in the late Neolithic era, and were a focus for ritual activity during the Bronze Age. Archaeological excavation in the 1980s proved that the main circle was erected 4,500-5,000 years ago, and the chambered tomb a few generations later. The setting has a unique arrangement, with lines of stones radiating in four directions from the ring. It is not fully clear whether the stone alignments were constructed at the same time as the ring, or later. The layout of the site, along with many others across the British Isles, appears to have an association with astronomical events, the precise nature of which cannot be determined.
Numerous other ritual sites lie within a few kilometres. These are mainly more modest rings of standing stones, or single monoliths. The most impressive Cnoc Ceann a' Ghàrraidh and Cnoc Fhillibhir Bheag lie just over a kilometre south-east of the main Calanais ring, and originally consisted of rings of stones at least eight in number.
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.