The building of St. Michael’s church in Kihelkonna was probably started in the mid-13th century and completed between 1270-1290. In the early Middle Ages Kihelkonna was one of the most important centers in Saaremaa. It was situated on the road connecting the western part of Saaremaa with mainland Estonia. There was also a harbor of considerable importance here. Both the Bishop and the Livonian Order contributed to the construction of the church, which was begun in the middle of the 13th century. Initially, a fortified western tower, as wide as the nave, had been planned but its construction was interrupted, apparently in its early stages, by the revolt of 1260-1261.
Inside the church the altarpiece (1591) and the pulpit (1604) are among the oldest of their kind in Estonia. Also worthy of mention is the organ, which was made in 1805 by J.A. Stein. It was reconstructed in 1890 by F. Weisseborn from Jekabpils in Latvia.
South of the church is located a distinct bell tower - so-called campanile. This stone-made, free standing bell tower was built in 1638 and is the only one remaining in Estonia. The tradition of such bell towers became widespread in Estonia in the 17th and 18th centuries.
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.