Colombier Castle was built in the 11th or 12th century as a fortified tower over the ruins of the Roman villa. It expanded in the 13th Century and by the 16th century had reached its present appearance.
One of the largest Roman era villas in Switzerland was excavated from under the castle in 1840-42 by Frédéric Dubois de Montperreux. It was built in multiple stages between the 1st and 3rd centuries AD into a palatial mansion with a peristyle, at least two baths with mosaics and frescoes and terraced gardens.
In 1806, Colombier Castle was converted into a military hospital. Starting in 1824 it was used by the Federal militias as a parade ground and was converted into a barracks and given an expanded arsenal. In 1877 it became the official barracks of the 2. Division, which later became Field Division 2. In 2003, the Army XXI reforms dissolved the Division and in 2004 the barracks became an infantry training center.References:
Roman Walls of Lugo are an exceptional architectural, archaeological and constructive legacy of Roman engineering, dating from the 3rd and 4th centuries AD. The Walls are built of internal and external stone facings of slate with some granite, with a core filling of a conglomerate of slate slabs and worked stone pieces from Roman buildings, interlocked with lime mortar.
Their total length of 2117 m in the shape of an oblong rectangle occupies an area of 1.68 ha. Their height varies between 8 and 10 m, with a width of 4.2 m, reaching 7 m in some specific points. The walls still contain 85 external towers, 10 gates (five of which are original and five that were opened in modern times), four staircases and two ramps providing access to the walkway along the top of the walls, one of which is internal and the other external. Each tower contained access stairs leading from the intervallum to the wall walk of town wall, of which a total of 21 have been discovered to date.
The defences of Lugo are the most complete and best preserved example of Roman military architecture in the Western Roman Empire.
Despite the renovation work carried out, the walls conserve their original layout and the construction features associated with their defensive purpose, with walls, battlements, towers, fortifications, both modern and original gates and stairways, and a moat.
Since they were built, the walls have defined the layout and growth of the city, which was declared a Historical-Artistic Ensemble in 1973, forming a part of it and becoming an emblematic structure that can be freely accessed to walk along. The local inhabitants and visitors alike have used them as an area for enjoyment and as a part of urban life for centuries.
The fortifications were added to UNESCO"s World Heritage List in late 2000 and are a popular tourist attraction.