Palmanova is a town in northeastern Italy and an excellent example of star fort of the Late Renaissance, built up by the Venetians in 1593.
Palmanova was built following the ideals of a utopia. It is a concentric city with the form of a star, with three nine-sided ring roads intersecting in the main military radiating streets. It was built at the end of the 16th century by the Venetian Republic which was, at the time, a major center of trade. It is actually considered to be a fort, or citadel, because the military architect Giulio Savorgnan designed it to be a Venetian military station on the eastern frontier as protection from the Ottoman Empire.
Between the points of the star, ramparts protruded so that the points could defend each other. A moat surrounded the town, and three large, guarded gates allowed entry. The construction of the first circle, with a total circumference of 7 kilometres, took 30 years.
References:The Broch of Clickimin is a large and well preserved, though somewhat restored broch near Lerwick. Originally built on an island in Clickimin Loch (now increased in size by silting and drainage), it was approached by a stone causeway. The water-level in the loch was reduced in 1874, leaving the broch high and dry. The broch is situated within a walled enclosure and, unusually for brochs, features a large 'blockhouse' between the opening in the enclosure and the broch itself. Another unusual feature is a stone slab featuring sculptured footprints, located in the causeway which approached the site. Situated across the loch is the Clickimin Leisure Centre.