Abbey of San Pietro al Monte is an ancient monastic complex of Romanesque style in the town of Civate. The site, presently not occupied by religious, consists of three buildings: the Basilica of San Pietro, the oratory dedicated to St. Benedict, and what was the monastery of which only ruin remain.
According a legend the abbey was founded in 772 AD by Desiderius, the last king of Lombardy. The oldest document dates from the 9th century. The monastery was destroyed in a war between city state of Milan and Frederick Barbarossa, the Holy Roman Emperor. The monks returned, but were expelled in 1798.
The buildings were part of the Benedictine abbey complex of Civate, the Basilica of San Calocero and the churches of San Nazario and San Vito. Two stone portals include engravings above them. The frescoes in the basilica of St. Peter, whose theme is the final apotheosis of Christ and the Triumph of the Righteous along the lines of the Apocalypse of St. John, makes it one of the most important Lombard Romanesque testimonies.
Carlsten is a stone fortress built on the orders of King Carl X of Sweden following the Treaty of Roskilde, 1658 to protect the newly acquired province of Bohuslän from hostile attacks. The site of Marstrand was chosen because of its location and its access to an ice free port. Initially a square stone tower was constructed, but by 1680 it was reconstructed and replaced by a round shaped tower. Successive additions to the fortress were carried out, by the inmates sentenced to hard labour, until 1860 when it was reported finished. The fortress was decommissioned as a permanent defense installation in 1882, but remained in military use until the early 1990s.
The fortress was attacked and sieged twice falling into enemy hands. In 1677 it was conquered by Ulrik Frederick Gyldenløve, the Danish military commander in Norway and in 1719 by the Norwegian Vice-Admiral Tordenskjold. At both occasions the fortress was returned to Swedish control through negotiations and treaties.